case study questions on acids bases and salts class 7

Acids Bases and Salts Class 7 Case Study Questions Science Chapter 4

Last Updated on August 26, 2024 by XAM CONTENT

Hello students, we are providing case study questions for class 7 science. Case study questions are the new question format that is introduced in CBSE board. The resources for case study questions are very less. So, to help students we have created chapterwise case study questions for class 7 science. In this article, you will find case study questions for cbse class 7 science chapter 4 Acids Bases and Salts.

Table of Contents

Case Study Questions on Acids Bases and Salts

Question 1:

Read the given passage below and answer the question:

Priya’s father was suffering from severe stomach pain. He was showing symptoms of heartburn and indigestion. He consulted a doctor who told him that he was suffering from acidity and advised him to take an antacid tablet after each meal. Priya’s father followed the advice strictly and was cured.

Q.1. Which acid is produced in our stomach? (a) Sulphuric acid (b) Hydrochloric acid (c) Nitric acid (d) Phosphoric acid

Difficulty Level: Easy

Ans. Option (b) is correct Explanation: The inner lining of the stomach secretes hydrochloric acid. It provides the acidic medium for digestion of food however, if the amount of acid produced in the stomach is exceeds then it causes indigestion and burning sensation.

Q.2. Antacids contain: (a) acid (b) base (c) salt (d) both (a) and (b)

Ans. Option (b) is correct. Explanation: Antacids are medicines which contain a base. They help to neutralise the excess acid present in the stomach.

Q.3. Milk of magnesia is an antacid which contains: (a) magnesium chloride (b) magnesium phosphate (c) magnesium hydroxide (d) magnesium nitrate

Difficulty Level: Difficult

Ans. Option (c) is correct. Explanation: Milk of magnesia is used as an antacid. It contains magnesium hydroxide which neutralises the effect of excessive acid.

Q.4. Explain how an antacid tablet gave relief to Priya’s father.

Ans. Hydrochloric acid is produced in our stomach which helps in digestion. However, when too much of acid produces, it causes indigestion. Antacid tablet contains base. When a tablet is taken, the base neutralise the effect of acid and gives relief from the problem of acidity.

Q.5. Is a glass of lemon water gives relief in indigestion? Why?

Difficulty Level: Medium

Ans. No, drinking lemon water during indigestion will not give relief because lemon juice is acidic in nature. Drinking lemonade may worsen the condition of indigestion.

Topics from which case study questions may be asked

• Define acid, base and salt.
• State examples of acid, base and salt.
• Discuss the properties of acids.
• Discuss the properties of bases
• Differentiate between acid and base.
• Define indicators.
• Give examples of indicators.
• Define neutralisation reaction.
• Describe neutralisation reaction.
• Discuss the importance of neutralisation reaction in everyday life.

For further practice on case study questions related to Class 7 Science Chapter 4 Acids Bases and Salts, we recommend exploring the link given below.

Frequently Asked Questions (FAQs) on Acids Bases and Salts Case Study Questions

Q1: what are case study questions for cbse examinations.

A1: Case study questions in CBSE examinations typically involve scenarios or real-life examples, requiring students to apply their understanding of concepts to solve problems or analyze situations.

Q2: Why are case study questions important for understanding class 7 science chapters?

A2: Case study questions provide a practical context for students to apply theoretical knowledge to real-world situations, fostering deeper understanding and critical thinking skills.

Q3: How do case study questions differ from other question types?

A3: Unlike direct questions that test specific knowledge, case study questions involve analyzing a scenario, understanding the context, and applying various scientific concepts to answer the questions. They test higher-order thinking skills such as analysis, synthesis, and evaluation.

Q4: Are there any resources available online for students to practice case study questions on class 7 science chapters for CBSE exams?

A4: Yes, several educational websites offer case study questions for CBSE students preparing for science examinations. We also offer a collection of case study questions for all classes and subject on our website. Visit our  website  to access these questions and enhance your learning experience. There is another website Physics Gurukul that offers a large collection of case study questions.

Q5: How can students effectively prepare for case study questions on acids, bases and salts for CBSE exams?

A5: Effective preparation strategies include regular revision of concepts, solving practice questions, analyzing case studies from previous exams, seeking clarification on doubts, and consulting with teachers or peers for guidance and support.

Q6: How can teachers incorporate case study questions on acids, bases and salts class 7 science into classroom teaching?

A6: Teachers can integrate case studies into lesson plans, group discussions, or interactive activities to engage students in active learning, promote problem-solving skills, and facilitate a deeper understanding of nutrition in plants.

Q7: What steps should I follow to correctly answer case study questions?

A7: Follow these steps: Read the case study carefully. Understand the scenario and the information provided. Identify the key concepts. Determine which scientific principles or concepts are relevant to the case study. Analyze the information. Break down the information, identify relationships, and note any data or facts given. Answer the questions. Apply your knowledge to answer the questions, ensuring that your responses are based on the case study and the relevant scientific concepts.

Q8: What should I check when reading a case study?

A8: Check the following: Context and background: Understand the setting and context of the case study. Key facts and data: Identify important details, data points, and observations mentioned. Relevant concepts: Recognize which scientific concepts and principles are applicable. Questions asked: Carefully read each question to understand what is being asked and how it relates to the case study.

Q9: What are common mistakes to avoid when answering case study questions?

A9: Common mistakes include: Not reading the case study carefully: Missing important details and context. Ignoring key concepts: Failing to identify and apply relevant scientific principles. Superficial analysis: Providing answers that lack depth and do not fully address the questions. Making assumptions: Adding information not provided in the case study or making unsupported assumptions.

Q10: How can I ensure my answers are thorough and well-structured?

A10: Ensure your answers are thorough and well-structured by: Organizing your thoughts: Structure your answer logically with a clear introduction, body, and conclusion. Using evidence: Support your answers with specific information from the case study. Applying relevant concepts: Clearly explain how scientific principles relate to the case study. Reviewing your answers: Check for completeness and accuracy, ensuring all parts of the question are addressed.

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NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12

Acids, Bases and Salts Class 7 Extra Questions Science Chapter 5

June 7, 2019 by Sastry CBSE

Acids, Bases and Salts Class 7 Science Extra Questions Very Short Answer Type Questions

Question 1. What is the test for acids and bases using litmus paper? Answer: Acids turn blue litmus paper red while bases turn red litmus paper blue.

Question 2. What name is given to those substances which do not change the colour of either red or blue litmus paper? Answer: The solutions or substances which do not change the colour of either red or blue litmus paper are neutral.

Question 3. Write the name of two indicators which occur naturally. Answer:

Question 4. Name the acid present in lemon juice and tomato. Answer: Citric acid in lemon juice and oxalic acid in tomato.

Question 5. Name a substance which is used to cure the discomfort caused by indigestion due to over eating. Answer: Milk of magnesia which contains magnesium hydroxide (base) is used to neutralise the effect of excessive acid in stomach.

Question 6. Why does a turmeric stain on white shirt is turned to red when it is washed with soap? [HOTS] Answer: Turmeric stain on white shirt is turned to red when it is washed with soap because the soap solution is basic in nature.

Question 8. Is lime water an acidic or basic solution? Answer: Lime water (calcium hydroxide) is a basic solution.

Question 9. Name the reaction when an acid is mixed with base. Answer: Neutralisation reaction.

Question 10. Which acid is injected into our body by an ant sting that causes pain? [HOTS] Answer: The acid is formic acid which is injected into the skin of a person when an ant bites.

Question 11. Name the salt formed when hydrochloric acid reacts with sodium hydroxide solution (a base). Answer: When hydrochloric acid reacts with sodium hydroxide solution, then sodium chloride salt is formed.

Question 12. Write two basic substances which we use in our daily life. Answer:

• Baking soda
• Soap or detergent

Question 13. Name one acid which is responsible for acid rain. Answer: Carbonic acid.

Question 14. Name two gaseous pollutants which are responsible for acid rain. Answer: Two gaseous pollutants are nitrogen dioxide (NO 2 ) and sulphur dioxide (SO 2 ).

Question 15. (a) Name one indicator which turns red on adding an acid. (b) Name one indicator which turns red on adding a base. Answer: (a) Litmus (blue litmus paper) (b) Turmeric

Question 16. Form a sentence using the following words: baking soda, ant bite, moist, effect, neutralised, rubbing [NCERT Exemplar; HOTS] Answer: The effect of an arft bite can be neutralised by rubbing moist baking soda.

Acids, Bases and Salts Class 7 Science Extra Questions Short Answer Type Questions

Question 1. Write the characteristics of acids by which we can identify acids. Answer: Characteristics of acids are

• They are sour in taste.
• They turn blue litmus paper/solution to red.
• Dilution of acid in water is an exothermic reaction, i.e. heat energy is evolved.

[NCERT Exemplar] Answer: Nature of solution is given below:

Question 3. While playing in a park, a child was stung by a wasp. Some elders suggested applying paste of baking soda and others lemon juice as remedy. Which remedy do you think is appropriate and why? [NCERT Exemplar; HOTS] Answer: Wasp sting inject a liquid in the skin which is acidic in nature. Hence, baking soda is the appropriate remedy as it is basic in nature and neutralises the acid.

Question 4. Which of the following are acidic and which are basic? Lime water, Vinegar, Toothpaste, Stomach juices, Lemon juice, Baking soda solution, Milk of magnesia, Ammonia solution. Answer:

Question 5. A small amount of hydrochloric acid is always produced in the stomach. Is it useful or harmful for us? If excess of acid is produced in the stomach, what should we do? Answer: A small amount of hydrochloric acid produced in the stomach is useful as it can kill the harmful bacteria that may enter into the stomach along with the food. However, if excess of acid is produced, there is a burning sensation in the stomach. We should take milk of magnesia as an antacid medicine to neutralise the excess acid.

Question 6. Write the effect of China rose petals on acidic and basic solutions. Answer: China rose petals when added to warm water, form a light pink coloured solution which may be used as an indicator. This indicator turns acidic solution to magenta (deep pink) and basic solution to green.

Question 7. To test the presence of an acid in any substance, what methods can be used? Answer: Acid can be tested in any substance by the following methods

• Take a drop of the dilute solution of the substance on the tips of your tongue. If tastes sour, it is acidic.
• Dip a blue litmus paper in the solution. If the colour of the litmus paper turns red, the solution is acidic.

Question 8. Why are sodium bicarbonate and lemon juice used during indigestion? Answer: Sodium bicarbonate neutralises the acidity in the stomach. Hence, it is used during indigestion. Lemon contains acid. It reacts with undigested food and suffers it.

Question 9. After carrying out the neutralisation reaction, the test tube immediately found to be somewhat hot. Explain why. Answer: In neutralisation reaction, heat is always produced or evolved. The evolved heat raises the temperature of the reaction mixture. Therefore, if we touch the test tube immediately after the neutralisation reaction, it is found to be hot. Acid + Base → Salt + Water (heat is evolved)

Question 10. Name three acids used in the laboratory. Answer: Acids which are mostly used in laboratory as below

• Hydrochloric acid (HCl)
• Sulphuric acid (H 2 SO 4 )
• Nitric acid (HNO 3 )

Question 11. Paheli is suffering from indigestion due to acidity. Is it advisable to give her orange juice in this situation and why? |NCERT Exemplar; HOTS] Answer: No, because orange juice is acidic in nature. Excess of acid in the stomach causes indigestion. We take an antacid such as milk of magnesia which contains magnesium hydroxide.

Question 12. Explain two neutralisation reactions related to daily life situations. Answer: (i) Ant bite When an ant bite injects the acidic liquid (formic acid) into the skin, the effect of the acid can be neutralised by rubbing moist baking soda (sodium hydrogen carbonate) or calamine solution, which contains zinc carbonate. (ii) Indigestion Our stomach contains hydrochloric acid. It helps us to digest food but too much of acid in the stomach causes indigestion. Sometimes, indigestion is painful. To relieve indigestion, we take an antacid such as milk of magnesia which contains magnesium hydroxide. It neutralises the effect of excessive acid.

Question 13. How lime water is prepared in the laboratory? Answer: To prepare lime water, dissolve some lime (chuna) in water in a bottle. Stir the solution and keep it for sometime. Pour a little more from the top. This is lime water.

Question 14. Name three types of salts. Give one example of each type of salt. Answer: Type of salts

• Neutral salts e.g. sodium chloride (NaCl)
• Acidic salts e.g. Ammonium chloride (NH 4 Cl)
• Basic salts e.g. sodium hydrogen carbonate (NaHCO 3 )

Question 15. Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the wastes of a factory in their village are flowing into the pond which probably caused the fish to die. (a) Explain why the fish were dying? (b) If the factory waste is acidic in nature, how can it be neutralised? [NCERT Exemplar; HOTS] Answer: (a) If the wastes of a factory flow into waterbodies, it can cause a threat to the lives of sea creatures and to anybody who drink the water. Since, factory wastes may contain acids or bases and it can kill the fish. (b) If the factory waste is acidic in nature, it can be neutralised by adding basic substances.

Question 16. What is a salt? Name any salt and give their formulae. Answer: A substance formed by the neutralisation of an acid with a base is called salt. Salt may be acidic, basic or neutral in nature. For example, Hydrochloric acid (HCI) + (Acid) Sodium hydroxide (NaOH) → (Base) Sodium chloride (NaCI) + Water (Salt) (Salt)

Question 17. Look at the given reaction. Hydrochloric acid + Sodium hydroxide (base) → Sodium chloride (salt) + Water Sodium chloride formed in this reaction remains in solution form. Can we get solid sodium chloride from this solution? Suggest a method (if any). [NCERT Exemplar] Answer: We can get solid sodium chloride by evaporation method. Evaporation is the process by which water changes from a liquid to a gas or vapour. Rate of evaporation increases with temperature.

Question 18. Name three bases used in the laboratory with their formulae. Answer: Bases which are mostly used in laboratory as below

• Sodium hydroxide (NaOH)
• Calcium hydroxide [Ca(OH) 2 ]
• Ammonium hydroxide (NH 4 OH)

Acids, Bases and Salts Class 7 Science Extra Questions Long Answer Type Questions

Question 1. A farmer was unhappy because of his low crop yield. He discussed the problem with an agricultural scientist and realised that the soil of his field was either too acidic or too basic. What remedy would you suggest the farmer to neutralise the soil? [HOTS] Answer: The reason for low crop yield in farmer’s field was that the soil at a place is either too acidic or too basic. The soil may be acidic or basic naturally. The excessive use of fertilisers in the fields also makes the soil too acidic. When the soil is too acidic, it is treated with base such as quicklime (calcium oxide) or slaked lime (calcium hydroxide) which neutralises the excess acid present in the soil and reduces its acidic nature. If the soil is too basic, then decaying organic matter (called manure or compost) is added it. The decaying organic matter releases acid which neutralises the excess bases present in the soil and reduces its basic nature.

Question 3. Boojho, Paheli and their friend Golu were provided with a test, each containing China rose solution which was pink in colour. Boojho added 2 drops of solution ‘A’ in his test tube and got dark pink colour. Paheli added 2 drops of solution ‘S’to her test tube and got green colour. Golu added 2 drops of solution ‘C but could not get any change in colour. Suggest the possible cause for the variation in their results. [HOTS] Answer: China rose (gudhal) is an acid-base indicator. China rose solution in different medium shows following changes: China rose + acid → Give dark pink colour, hence A is an acidic solution. China rose + base → give green colour, hence 6 is a basic solution. China rose + neutral → No change in colour, hence C is a neutral solution.

Question 4. Nitesh was playing with his friends in the garden. Suddenly, Nitesh was stung by a honeybee and was in great pain. Immediately, his friends call his mother. She applied baking soda solution on the affected area and then took him to the doctor. Read the above passage and answer the following questions: (a) What could be the reason for this burning pain? (b) Why did his mother applied baking soda solution on the affected area? (c) What values are shown by Nitesh’s friends? [Value Based Question] Answer: (a) The reason for this burning pain is honeybee sting which causes pain and irritation. This is due to the acidic liquid (formic acid) injected into the skin by the honeybee. (b) The effect of acid can be neutralised by rubbing the affected area by baking soda solution which is a mild base. (c) Nitesh’s friends are caring , supportive and helpful.

Question 5. One day Rahul’s mother after taking meal felt pain and irritation in her stomach. His father was out of station. Rahul was an intelligent boy. He remembered his teacher’s statement and gave his mother some baking soda solution Which gave her a relief from pain and irritation of stomach. Read the above passage and answer the following questions. (a) Which information given by Rahul’s teacher that helped him to select the baking soda as remedy? (b) Why he selects baking soda as a cure? (c) What values are shown by Rahul? [Value Based Question] Answer: (a) Rahul knows that our stomach contains hydrochloric acid. It helps us to digest food. But, too much acid in the stomach causes indigestion. Sometimes, indigestion is painful and some mild base should be taken to relief from this pain. So, this information given by his teacher helped him. (b) He gave her mother baking soda solution which was available in the kitchen easily. He selects baking soda because it is a mild base and neutralises the excess acid in the stomach and it will give relief from pain. (c) Rahul is very intelligent and caring boy.

Acids, Bases and Salts Class 7 Science Extra Questions Miscellaneous Questions

Multiple Choice Questions Question 1. The correct way of making a solution of acid in water is to [NCERT Exemplar] (a) pdd water to acid (b) add acid to water (c) mix acid and water simultaneously (d) add water to acid in a shallow container Answer: (b) add acid to water

Question 2. Products of a neutralisation reaction are always (a) an acid and a base (b) an acid and a salt (c) a salt and water (d) a salt and a base Answer: (c) a salt and water

Question 3. Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed? (a) Yellow in both acid and base (b) Yellow in acid and red in base (c) Pink in acid and yellow in base (d) Red in acid and blue in base Answer: (b) Yellow in acid and red in base

Question 4. Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions respectively are [NCERT Exemplar] (a) red and blue (b) blue and red (c) pink and colourless (d) colourless and pink Answer: (d) colourless and pink

Question 5. When the soil is too basic, plants do not grow well in it. To improve its quality, what must be added to the soil? [NCERT Exemplar] (a) Organic matter (b) Quicklime (c) Slaked lime (d) Calamine solution Answer: (a) Organic matter

Question 6. Neutralisation reaction is a [NCERT Exemplar] (a) physical and reversible change (b) physical change that cannot be reversed (c) chemical and reversible change (d) chemical change that cannot be reversed Answer: (d) chemical change that cannot be reversed

Question 7. A solution changes the colour of turmeric indicator from yellow to red. The solution is (a) basic (b) acidic (c) neutral (d) either neutral or acidic Answer: (a) basic

Question 8. Which of the following sets of substances contains acids? (a) Grapes, lime water (b) Vinegar, soap (c) Curd, milk of magnesia (d) Curd, vinegar Answer: (d) Curd, vinegar

Question 9. Which of the following is an acid-base indicator? [NCERT Exemplar] (a) Vinegar (b) Lime water (c) Turmeric (d) Baking soda Answer: (c) Turmeric

Fill in the Blanks 1. Lemon juice and vinegar taste ……………… because they contain ……………… . [NCERT Exemplar] 2. Turmeric and litmus are ……………… acid-base indicators. 3. Phenolphthalein gives ……………… colour with lime water. 4. When an acidic solution is mixed with a basic solution, they ……………… each other forming ……………… and water. [NCERT Exemplar] 5. The acidic or basic nature of a substance is tested by using an ……………… . 6. The substances which show different colours in acidic, basic and neutral solutions are called ……………… 7. Acid + Base → ……………… + Water 8. When an acid mixed with a base, a ……………… reaction takes place. 9. Acetic acid is present in ……………… while ……………… is present in lemon. 10. Excessive use of chemical fertilisers make the soil ……………… . 11. Hydrochloric acid + Sodium hydroxide → ……………… + Water 12. Acids turn blue litmus ……………… . Answers: 1. sour, acids 2. natural 3. pink 4. neutralise, salt 5. indicator 6. indicators 7. salt 8. neutralisation 9. vinegar, citric acid 10. acidic 11. Sodium chloride 12. redTrue/False

True/False 1. All substances are either acidic or basic. [NCERT Exemplar] 2. A compound if acidic will turn all indicators red. 3. Lime water turns red litmus blue. [NCERT Exemplar] 4. Common salt dissolved in water turns blue litmus red. 5. Phenolphthalein is a natural indicator. 6. Calamine can be used to treat ant’s sting. 7. Lemon water is basic in nature. Answers: 1. False, substances can be neutral as well. 2. False, acids do not turn all indicators red. 3. True 4. False, it does not change the colour of litmus at all. 5. False, it is a man-made indicator. 6. True 7. False, it is acidic in nature.

Match the Columns Question 1. Match the substances in Column I with those in Column II.

Question 2. Match the items in Column 1 with Column II.

Answers: 1. (a)-(iii) (b)-(v) (c)-(iv) (d)-(i) (e)-(ii)

2. (a)-(ii) (b)-(iii) (c)-(iv) (d)-(i)

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Important Questions Class 7 Science Chapter 5

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Important Questions Class 7 Science Chapter 5 – Acids, Bases, and Salts

Class 7 Science Chapter 5 is one of the most important chapters, which teaches about Acids, Bases, and Salts found in the substances we use daily and how they are formed. Acids are sour. Examples of acidic substances are lemon, curd, vinegar, etc. Bases like baking soda are bitter in taste and soapy to the touch. Salt is formed as a result of acid and base neutralisation reactions. Furthermore, this chapter covers some important topics: acids and bases, natural indicators around us, neutralisation, and neutralisation in everyday life

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A comprehensive list of Science Class 7 Chapter 5 Important Questions is taken from the NCERT textbook, NCERT exemplars, etc., for students to help revise the topics thoroughly and score well in the examination. Our question bank of Important Questions Class 7 Science Chapter 5 is a useful tool for students to solve a lot of exam-oriented questions. The question bank comes with detailed self-explanatory solutions that will help students revise the chapter fully while solving the questions.

Important Questions Class 7 Science Chapter 5 – With Solutions

Chapter 5, Class 7, Science Important questions are extremely helpful for students preparing for CBSE examinations. The Extramarks team understands that regularly solving questions will help students revise the subject and also retain their knowledge of the topics.

Hence, our team of expert science teachers have prepared a comprehensive list of Science Class 7 Chapter 5 Important Questions including textbook exercise questions and answers, MCQs, short answer questions, and long answer questions taken from the NCERT textbook, NCERT exemplars, etc. Students should solve these important questions while revising the chapter to clarify all the doubts.

You can register on the Extramarks website to access and practise our Important Questions for Class 7 Science Chapter 5 and other chapter-wise questions.

The below-given list consists of a few questions and their answers from our Class 7 Science Chapter 5 Important Questions:

Question 1. State the differences between acids and bases with examples.

Answer 1.  

• Acids: The acidic chemical substances are called acids. These substances taste sour—for example, curd, lemon juice, vinegar, and tamarind.
• Bases: The nature of such substances is basic. These substances taste bitter and feel soapy on touching, for example, baking soda and milk of magnesia.

Question 2. The appropriate method of preparing an acid solution in water is, 

(a) Add water to acid.

(b) Add acid to water.

(c) Add water to acid in a shallow container.

(d) Mix acid and water simultaneously

Answer 2. (b) Add acid to water.

Explanation: Adding water to a concentrated acid releases a huge amount of heat due to an exothermic reaction and leads to explosions. Hence, adding acid to water is the correct way to make a solution of acid.

Question 3. Give any two names of the indicators that occur naturally.

Answer 3.  

Question 4. Explain the neutralisation process with the help of an example.

Answer 4. A basic solution is mixed with an acidic solution in the neutralisation process.

The resulting solution is neither acidic nor basic,, as both the acidic nature of the acid and the basic nature of the base are destroyed. Water and salt are produced in this process with the evolution of heat.

Below is an example of neutralisation

Hydrochloric acid (HCl) + Sodium hydroxide (NaOH) → Sodium chloride (NaCl) + Water (H2O)

Question 5. State whether the below-given statements are true or false. Correct the false statements.

(a) A compound, if acidic, will turn all indicators red.

(b) All the substances are either acidic or basic.

(c) Common salt dissolved in water turns blue litmus red.

(d) Lime water turns red litmus blue.

(e) Phenolphthalein is a natural indicator.

(f) Calamine can be used to treat ant stings.

(g) Lemon water is basic.

• False. Acidic compounds will not turn all indicators red.
• False. All substances are classified as acidic, basic or neutral.
• False. As it is a neutral solution, the colour of the litmus paper will not change.
• False. Phenolphthalein is an artificial indicator.
• False. Lemon water is acidic.

Question 6. Consider the following statements:

(a) Both acids and bases change the colour of all indicators.

(b) If an indicator gives a colour change with an acid, it does not give a change with a base.

(c) If an indicator changes colour with a base, it does not change colour with an acid.

(d) The change of colour in an acid and a base depends on the type of indicator.

Which of these statements is correct?

(i) All four 

(ii) a and d 

(iii) b, c and d 

(iv) only d

Answer 6. (iv) Only d

Explanation : 

(a) Not all indicators cause acidic or basic substances to change colour. For example, the phenolphthalein indicator used in the neutralisation process is colourless in acid but changes to pink in bases.

(b) Indicators can give a colour change for both acid and base. For example, When a litmus solution is added to an acidic solution, it turns red, and when added to a basic solution, it turns blue.

(c) An indicator that changes colour when exposed to a base can or cannot change colour when exposed to acid.

For example, the turmeric indicator changes to red in the base but does not show any colour change in the acid.

(d) Hence, the change of colour in an acid and a base depends on the type of indicator and is the correct answer.

Question 7. Fill the blanks in the below-given sentences

(a) Turmeric and litmus are _________ acid-base indicators.

(b) Lemon juice and vinegar taste ___________ because they contain ___________.

(c) When an acidic solution is mixed with a basic solution, they _________ each other forming _________ and water.

(d) Phenolphthalein gives _________ colour with lime water.

(a) Natural

(b) Sour, acids

(c) Neutralise, salt

Question 8. Explain two neutralisation reactions related to daily life Situations.

Answer 8. The two neutralisation reactions related to our daily life situation are,

• Indigestion: Excessive hydrochloric acid in the stomach causes indigestion. To neutralise the effect of excessive acid and relieve indigestion, we take an antacid such as milk of magnesia, which contains magnesium hydroxide.
• Ant bite: When an ant bites, it injects formic acid into the skin. Rubbing the moist baking soda, which contains sodium hydrogen carbonate or calamine solution containing zinc carbonate, can neutralise the effect of the acid.

Question 9. Mark true or false for the below statements. Correct the false statements.

(a) Nitric acid turns red litmus blue.

(b) Sodium hydroxide turns blue litmus red.

(c) Sodium hydroxide and hydrochloric acid neutralise each other and

produce water and salt. 

(d) Indicator shows different colours in acidic and basic solutions. 

(e) Tooth decay is caused due to the presence of a base. 

(a) False. Nitric acid is acidic. Substances with an acidic nature will turn the blue litmus paper red.

(b) False. Sodium hydroxide is basic. Substances of a basic nature will turn the red litmus paper blue. If we use blue litmus paper, it will not change the colour.

(e) False. Tooth decay is caused due to the degradation of food particles that get stuck in the teeth, and the bacteria ( Streptococcus ) consume them to convert the glucose, fructose, and sucrose of the food items into lactic acid. The high level of lactic acid accumulated in the teeth leads to the fermentation of more sugars and creates plaque and cavities, which, when not taken care of for a long time, can cause tooth decay.

Note: The presence of a base substance neutralises the acid and protects it from tooth decay.

Question 10. Look at the given reaction.

Hydrochloric acid + Sodium hydroxide (base) → Sodium chloride (salt) + Water

Sodium chloride formed in this reaction remains in solution form. Can we get solid sodium chloride from this solution? Suggest a method (if any).

Answer 10. Yes, we can get solid chloride from the solution by evaporation process.

The water evaporates and forms sodium chloride crystals by heating the sodium chloride solution.

Question 11. Match the substances in Column I with those in Column II.

Answer 11. The matched substances are given below,

Question 12. Frame a sentence using the following words – baking soda, ant bite, moist, effect, neutralised, rubbing.

Answer 12. The effect of an ant bite can be neutralised by rubbing the moist baking soda.

Question 13. Ammonia can be found in many household products, such as window cleaners. It turns red litmus blue. What is its nature?

Answer 13. Ammonia is basic. Hence, it turns red litmus blue.

Ammonia is classified as a weak base, as its molecules don’t completely break down into ions in water.

Question 14. When the soil is too basic, plants do not grow well in it. To improve its quality, what must be added to the soil?

(a) Organic matter

(b) Slaked lime

(c) Quick lime

(d) Calamine solution

Answer 14. (a) Organic matter

Explanation: When the soil is too basic, the fertility of the soil is reduced, and plants do not grow well. We must add organic matter to replenish soil fertility, as it releases acids that react and neutralise the excess base in the soil.

Question 15. Which of the following is an extract of ‘Litmus,’ a natural dye?

(a) China rose (Gudhal)

(b) Beetroot

(d) Blueberries (Jamun)

Answer 15. (c) Lichen

Explanation: Litmus is extracted from lichen algae living among the strands of multiple fungi species. Litmus paper is commonly used as an acid-base indicator.

Question 16. What is acid rain?

Answer 16. Due to excess air pollutants such as carbon dioxide, sulphur dioxide and nitrogen dioxide released into the air, the raindrops dissolve all of these pollutants to form carbonic acid, sulphuric acid and nitric acid, Acid rain can cause damage to plants, and animals, buildings, and historical monuments.

Question 17. What are salts? Explain with the help of an example.

Answer 17. Salt and water are produced in the neutralisation reaction between acid and base. Salt may be acidic, basic or neutral. For Example

From the above reaction, sodium chloride is produced in the form of salt.

Benefits of Solving Important Questions Class 7 Science Chapter 5

Important Questions Class 7 Science Chapter 5 consists of all types of questions, including MCQs, short and medium-format questions and answers, CBSE extra questions, and long-answer questions with step-by-step solutions to make students well-versed with various questions appearing in the CBSE examination.

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• Important Questions Class 7 Science Chapter 5 has detailed solutions to all the questions in the textbook. Also, the tricky questions between chapters make students think laterally and apply the concepts learned in the chapter.
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Q.1 Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and the third is a sugar solution. How will you identify them when you are only provided with turmeric powder?

Ans Turmeric solution turns red in contact with bases and is not affected by acids and neutral substances. So, we put turmeric indicator in some portions of all the three liquids labeled as A, B, and C respectively. ‘B’ would turn red, indicating that it is a base.

Then, one of the liquids ( A or C) is added to the solution of sodium hydroxide and turmeric powder. If the solution turns yellow, the added liquid is hydrochloric acid because acid neutralises the base. Otherwise, if no change is observed, the added liquid is the sugar solution.

Q.2 How does hydrochloric acid help in the digestion of food?

HCl plays an important role in the digestion of food in our stomach. HCl makes the medium acidic, so that gastric enzymes may act on the food. It also kills the disease causing germs that come along with the intake of food.

Q.3 Select the correct match.

(a). a – p, b – q, c – s, d – r

(b). a – q, b – s, c – p, d – r

(c). a – r, b – s, c – p, d – q

(d). a – r, b – p, c – s, d – q

Q.4 The acidic soil is not good for healthy growth of plants. This type of soil is neutralized by adding

(a). ammonium chloride (NH 4 Cl) to the soil.

(b). calcium oxide (CaO) to the soil.

(c). sodium chloride (NaCl) to the soil.

(d). organic matter to the soil.

This soil is neutralized by adding calcium oxide (CaO), which is basic in nature.

Q.5 An example of synthetic indicator is

(a). litmus

(b). phenolphthalein

(c). turmeric

(d). china rose extract

Phenolphthalein is a synthetic indicator, which is colourless and changes its colour to pink in basic medium.

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NCERT Class 7 Science Chapter 5 Acids, Bases and Salts Extra Questions

Ncert class 7 science chapter 5 acids, bases and salts extra questions and answers.

Class 7 Science Chapter 5 Extra Questions and Answers – Acids, Bases and Salts. Here in this Page Class VII Students can Learn Extra Questions & Answer 5th Chapter Science fully Inside.

Class 7 Science Chapter 5 Extra Question with Answer – Acids, Bases and Salts

1) Fill in the blanks:

b) ___acid is found in curd.(Lactic)

2) Multiple choice questions:

Ans. b) Hydrochloric

e) ___acid is found in amla?

a) Ascorbic b) Lactic c) Acetic

Ans. The substances which are neither acidic nor basic are called neutral substances.

Ans. The solutions of substances that show different color in acidic, basic and neutral solutions are called indicators.

d) Why should the factory waste neutralize before disposing it into the water body?

Ans. The waste of many factories contain acids. If they are allowed to flow into the water bodies, the acids will kill fish and other organisms. The factory waste should, therefore, neutralize before disposing it into the water body.

I.) Both A and R are true and R is the correct explanation of A.

V.) Both A and R are false.

6) When an ant bites, it injects the acidic liquid into the skin. The effect of the acid can be neutralized by rubbing moist baking soda or calamine solution, which contains zinc carbonate.

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NCERT Solutions for Class 7 Science Chapter 5 Acids, Bases and Salts

NCERT Solutions for CBSE Class 7 Science Chapter 5 Acids, Bases and Salts are given below. These solutions help students to clear their doubts and to obtain good marks in final exam. Class 7 Science NCERT questions and answers provided in this article are strictly based on the CBSE syllabus and curriculum.

Class 7 Science Chapter 5 Acids, Bases and Salts NCERT Solutions

Class 7 NCERT Solutions for Science Chapter 5 includes all the intext and exercise questions. All these questions are solved by experts with a detailed explanation that will help students complete their assignments and homework.

Question 1: State differences between acids and bases.

Question 2: Ammonia is found in many household products, such as window cleaners. It turns red litmus blue. What is its nature?

Answer: Bases turn red litmus blue, so nature of ammonia is basic.

Question 3: Name the source from which litmus solution is obtained. What is the use of this solution?

Answer: Litmus is extracted from lichens. It has a mauve (purple) colour in distilled water. When added to an acidic solution, it turns red and when added to a basic solution, it turns blue. So, it is used to test the acidic or basic nature of solutions.

Question 4: Is the distilled water acidic/basic/neutral? How would you verify it?

Answer: Distilled water is neutral by nature. We can verify it by litmus test. Water does not change the colour of either red or blue litmus. This proves that distilled water is neutral.

Question 5: Describe the process of neutralisation with the help of an example.

Answer: The reaction between an acid and a base is known as neutralization reaction. In this reaction, both acid and base cancel each other’s effect. Neutralisation reaction results in the formation of salt and water. During this reaction, energy in the form of heat is evolved.

Acid + Base → Salt + Water + Heat

For example: when sodium hydroxide (NaOH) is added to hydrochloric acid (HCl), sodium chloride (NaCl) and water (H 2 O) are obtained.

NaOH + HCl → NaCl + H 2 O + Heat

Question 6: Mark ‘T’ if the statement is true and ‘F’ if it is false:

(i) Nitric acid turns red litmus blue. (T/F)

(ii) Sodium hydroxide turns blue litmus red. (T/F)

(iii) Sodium hydroxide and hydrochloric acid neutralise each other and form salt and water. (T/F)

(iv) Indicator is a substance which shows different colours in acidic and basic solutions. (T/F)

(v) Tooth decay is caused by the presence of a base. (T/F)

Answer: (i) False (ii) False (iii) True (iv) True (v) False

Question 7: Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?

Answer: Dorji can use litmus test on these drinks. Just drop few drops of drink on litmus paper and take the decision according to the following:

Question 8: Explain why:

(a) An antacid tablet is taken when you suffer from acidity.

(b) Calamine solution is applied on the skin when an ant bites.

(c) Factory waste is neutralised before disposing it into the water bodies.

Answer: (a) Due to release of excess of hydrochloric acid, we suffer from acidity. An antacid tablet consists of a base like Milk of Magnesia (magnesium hydroxide). It neutralizes the effect of excessive acid and brings relief.

(b) When ant bites, it injects formic acid inside the skin. Calamine consists of Zinc carbonate which is basic in nature. Hence calamine neutralises the effect of formic acid to bring relief for the affected person.

(c) Factory wastes contain acids. Therefore, these wastes, when thrown directly to water bodies, harm aquatic lives. Hence, these wastes are neutralised with basic chemicals before disposing to water bodies.

Question 9: Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar solution. How will you identify them? You have only turmeric indicator. 

Answer: The following steps are taken to test the given liquids:

• Put a drop of provided liquid on the turmeric indicator. The solution that changes the colour of the indicator to red, is sodium hydroxide, which is basic in nature.
• Now, to make two mixtures, add a drop of sodium hydroxide on the other two liquids individually.
• The drop of each combination added to the turmeric indicator one after another.
• The mixture that changes the indicator to red colour includes a neutral solution of sugar.
• While the mixture contains hydrochloric acid that has been neutralized by the addition of sodium hydroxide, which does not show any colour change in the indicator.

Question 10: Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.

Answer: If a blue litmus paper when dipped in a solution, remains blue, it implies the solution is either basic or neutral.

Question 11: Consider the following statements:

(a) Both acids and bases change colour of all indicators.

(b) If an indicator gives a colour change with an acid, it does not give a change with a base.

(c) If an indicator changes colour with a base, it does not change colour with an acid.

(d) Change of colour in an acid and a base depends on the type of the indicator.

Which of these statements are correct?

(i) All four (ii) a and d  (iii) b and c (iv) only d

Answer: (iv) only d

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Important Questions for CBSE Class 7 Science Chapter 6 - Physical and Chemical Changes

• Class 7 Important Question
• Chapter 6: Physical And Chemical Changes

CBSE Class 7 Science Chapter-6 Important Questions - Free PDF Download

Free PDF download of Important Questions with solutions for CBSE Class 7 Science Chapter 6 - Physical and Chemical Changes prepared by expert Science teachers from the latest edition of CBSE (NCERT) books is available here. Register Online for NCERT Solutions Class 7 Science tuition on Vedantu.com to score more marks in the CBSE board examination. 

Vedantu is a platform that provides free CBSE Solutions (NCERT) and other study materials for students. Maths students who are looking for better solutions can download Class 7 Maths NCERT Solutions to help you to revise the complete syllabus and score more marks in your examinations.

Topics Covered in Chapter 6 Physical and Chemical Changes of CBSE Class 7 Science

Physical change

Chemical change

Rusting of iron

Crystallisation

Study Important Questions for Class 7 Science Chapter 6 – Physical and Chemical Changes

Very short answer questions (1 mark).

1. Identify the following changes as physical or chemical.

a. Dissolving sugar in water.

Ans: Physical.

b. Formation of rain from clouds. 

c. Formation of acid rain 

Ans: Chemical.

d. Combustion 

e. Hammering a nail flat.

Short Answer Questions (3 Marks)

2. What are physical properties? Give examples.

Ans: Physical characteristics are features of a substance that may be determined based on its appearance. 

Examples: shape, size, colour, state of compound etc.

3. What are chemical changes? Give examples.

Ans: When one or more compounds react to generate completely new products, this is referred to as a chemical change. The original reactant or substance changes totally as a result of a chemical transformation. The final product is unique. The transformation is irreversible.  

Examples: Combustion, corrosion, photosynthesis etc.

4. What are physical changes? Give examples.

Ans: Physical changes occur in a matter that does not result in the creation of a new product. During these transitions, the matter often shifts from one state to another. For example, changes in the state of matter, the solubility of salt and sugar in water, and so on.

5. Explain how burning a strip of magnesium ribbon is a chemical change.

Ans: When magnesium ribbon is burned in the presence of air, it produces white ash with a dazzling white light which is known as magnesium oxide. The ashes formed look physically different in appearance from the initial reactant. It is a chemically unique matter at the same time. Burning magnesium ribbon is an example of a chemical shift because the product is an entirely different compound.

6. What happens when vinegar is added to baking soda? How do you test the gas produced?

Ans: Vinegar is acidic in nature on the other hand baking soda is basic in nature. When we combine these two salts, water along with carbon dioxide gas is formed.

The gas produced is passed through lime water. The lime turns milky or white due to the formation of calcium carbonate. This test confirms the presence of carbon dioxide.

Long Answer Questions (5 Marks)

7. What are the indications of a chemical change?

Ans: The following signs of chemical change are present: 

Heat may be absorbed or released in the reaction.

There might be the production of sound during or at the end of the reaction.

A pleasant or pungent odour is created.

A change in the colour of the solution may occur.

Formation of gas.

8. Explain the formation of rust.

Ans: The degrading of metals such as iron in response to the environment is known as rusting. When it comes to oxygen and water, iron is extremely reactive. The production of iron oxide from iron is referred to as rust. It causes the iron article to deteriorate. Rust  (Iron III oxide) is formed when iron combines with oxygen and water. Rust starts on the surface and works its way deeper into the metal.

Iron (Fe) + Oxygen (O₂) (from the air) + water (H 2 O) rust (iron oxide Fe 2 O 3 )

9. How can rusting of iron be prevented? Suggest and explain any three methods.

Ans: Rusting is a phenomenon that occurs on the surface of a metal. It can be avoided in the following ways:

Applying oil or grease on the surface inhibits the iron surface from coming into touch with the atmosphere, which prevents rusting.

Galvanization: A layer of a more reactive metal, such as zinc, is deposited on the surface of iron to protect it from rust.

Painting: Applying a layer of paint to the metal's surface stops it from coming into contact with the atmosphere once more.

Alloying: To make alloys, iron can be combined with other metals and non-metals. Rust resistance is a feature of alloys. Stainless steel is an important iron alloy.

Benefits of Referring to the Important Questions of Class 6 - Physical and Chemical Changes

Students must go through the important questions of each chapter of Science, but why? Some of the reasons for this have been listed below:

These questions help you to evaluate your knowledge and understanding of any particular chapter.

If you refer to other questions that are not given in your NCERT book, then you will prepare yourself for the examination paper where the teacher might ask you some tricky questions.

It also helps you to understand the topic in depth.

These notes are error-free and adhere to the CBSE standards.

It helps students' thinking ability and problem-solving abilities, which help students to secure good marks not in the current class, but in all academic sessions. 

These notes are prepared by expert and experienced Science teachers and subject matter experts having in-depth knowledge of the topics covered in this chapter.

These notes are error-free and adhere to the CBSE standards. Hence, students can reliably refer to these notes while preparing for their exams. 

With these notes, students can evaluate their understanding of the chapter and find the loopholes, if any. 

These notes follow the latest syllabus prescribed by the CBSE and cover important questions in Chapter 12 of the NCERT book. 

Students can easily download the PDF at no cost and study them offline too.

Students can also download the PDF of solutions for NCERT exercises in Science and other subjects. They can also access other study material from our website free of cost.  We hope all the students find the study material useful for their preparation and score well in the exams. 

NCERT Class 7 Science Chapter wise Solutions 

Chapter 1 - Nutrition in Plants

Chapter 2 - Nutrition in Animals

Chapter 3 - Fibre to Fabric

Chapter 4 - Heat

Chapter 5 - Acids, Bases and Salts

Chapter 7 - Weather, Climate and Adaptations of Animals to Climate

Chapter 8 - Winds, Storms and Cyclones

Chapter 9 - Soil

Chapter 10 - Respiration in Organisms

Chapter 11 - Transportation in Animals and Plants

Chapter 12 - Reproduction in Plants

Chapter 13 - Motion and Time

Chapter 14 - Electric Current and Its Effects

Chapter 15 - Light

Chapter 16 - Water: A Precious Resource

Chapter 17 - Forests: Our Lifeline

Chapter 18 - Wastewater Story

Importances about Important Questions for CBSE Class 7 Sciences Chapter 6- Physical and Chemical Changes

The importance of "Important Questions for CBSE Class 7 Science Chapter 6 - Physical and Chemical Changes" lies in their role as a strategic learning tool. This chapter delves into the fundamental concepts of chemistry, distinguishing between physical and chemical changes in matter. These important questions serve as a targeted and efficient means of revision, helping students reinforce their understanding of the chapter's key principles.

Moreover, they prepare students comprehensively for examinations by covering a wide range of topics and question types, similar to what they might encounter in tests and assessments. By tackling these questions, students not only assess their knowledge but also develop problem-solving skills, critical thinking, and analytical abilities.

Furthermore, these questions encourage practical application of chemistry principles in real-world scenarios, fostering an appreciation for the relevance of science in daily life. In essence, these important questions empower students to excel academically while nurturing their scientific curiosity and understanding of the dynamic world of chemistry.

Conclusion 

"Important Questions for CBSE Class 7 Science Chapter 6 - Physical and Chemical Changes" are a valuable resource that holds immense significance in a student's scientific education. This chapter explores the intriguing realm of chemistry by distinguishing between physical and chemical changes in matter. The importance of these questions lies in their ability to serve as a comprehensive revision aid, consolidating students' understanding of essential scientific principles. They play a pivotal role in exam preparation, offering a diverse range of question types that mirror what students may encounter in assessments. Furthermore, these questions foster critical thinking and problem-solving skills, instilling a deeper appreciation for the practical relevance of chemistry in our daily lives. Overall, they empower students to excel academically while nurturing their curiosity about the ever-evolving world of science.

FAQs on Important Questions for CBSE Class 7 Science Chapter 6 - Physical and Chemical Changes

1. How many questions are present in Chapter 6 of Class 7 Science?

In the textbook, questions are given at the end of each chapter. Writing answers to these questions help you to gauge your level of understanding of the concept taught. At the same time, it also encourages you to think and recall. All of these skills will be required in every exam that you write. There are 12 questions given at the end of Chapter 6 of Class 7. Extra four questions are given for the purpose of extended learning.

2. What are the important topics in the Chapter 6 of NCERT Solutions for Class 7 Science?

Chapter 6 of Class 7 explains the difference between physical and chemical changes. We come across several of these changes but we can hardly notice them. It is important to understand the concepts of physical and chemical changes and the difference between them. It is also crucial that you memorize some of the equations that you can cite as examples in the exam. Understand the process of rusting, galvanization and crystallization. Make short notes on them. They will come in handy.

3. Explain the process of rusting with the help of an equation.

Iron is a meal that is of immense significance. Discovery of iron thousands of years back has revolutionized our way of life. Iron is present in the house we live in, buildings we work or study in, the cars we travel in and our highways and airplanes. Oxygen and water present in the environment reacts with the iron. When the moisture in the air is high, rusting gathers pace. The process of rusting can also be explained by the equation: Iron + Oxygen + Water -> Rusting.

4. What is galvanisation and why is it needed?

Galvanization is the process in which a layer of zinc is deposited on iron to prevent it from rusting. A layer of zinc prevents the molecules of oxygen and water from coming in contact with the iron. One can also apply paint or grease. Galvanization is needed because iron is an important part of all of our infrastructures. Rusting destroys the quality of the infrastructure and also weakens it. Rusting causes monetary loss as a huge amount of money is invested in buildings, houses, highways, etc.

5. Do I have to practice questions of Chapter 6 Class 7 Science?

Chapter 6 of Class 7 introduces you to the concept of physical and chemical changes. The concept forms the basis of your higher classes. You will be introduced to several concepts in-depth in your higher classes that will be building upon this chapter’s foundation. Practising questions given in the textbook helps you to analyze how well you have understood the concept. The more questions you practice, the more your understanding will be consolidated. Do not cram the information given. Understand the basics and then practice the questions and revise.

Chapterwise Important Questions for CBSE Class 7 Science

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7th Class Science Acids, Bases and Salts / अम्ल, क्षार एवं लवण Question Bank

Done acids, bases and salts total questions - 130.

question_answer 1) Acid present in soured curd is

A) Lactic acid       done clear

B) Acetic acid done clear

C) Tartaric acid                done clear

D) Oxalic add done clear

question_answer 2) Which of the following acid is used by gold smith for dissolving gold?

A) Nitric acid                    done clear

B) Sulphuric acid done clear

C) Aqua regia                   done clear

D) Hydrochloric acid done clear

question_answer 3) Which of the following substance present in turmeric changes its colour on reaction with base?

A) Lichen                         done clear

B) Magnesia done clear

C) Curcumin        done clear

D) None of these done clear

question_answer 4) Which of the following is not an indicator?

A) China rose      done clear

B) Onion done clear

C) Clove                           done clear

D) Lemon done clear

question_answer 5) Sodium bicarbonate is commonly called

A) Lime water                  done clear

B) Slaked lime done clear

C) Washing soda              done clear

D) Baking soda done clear

question_answer 6) Complete the following analogy: Turmeric: Indicator:: Milk of magnesia:

A) Strong acid                  done clear

B) Antacid done clear

C) Antidote for sting         done clear

D) Hydrated salt done clear

question_answer 7) Complete the following analogy: Sea water : Salty:: ______: Soap

A) Bitter                            done clear

B) Slippery done clear

C) Sour                             done clear

D) Both (a) and (b) done clear

question_answer 8) Which one of the following salts is used for making detergent powder?

A) Washing soda  done clear

B) Potassium nitrate done clear

C) Sodium bicarbonate    done clear

D) Common salt done clear

question_answer 9) Which of the following is not a base?

A) Magnesium hydroxide done clear

B) Calcium hydroxide done clear

C) Calcium carbonate done clear

D) Sodium hydroxide done clear

question_answer 10) Antacids contain -

A) Strong acid                  done clear

B) Weak base done clear

C) Strong base                  done clear

D) Weak acid done clear

question_answer 11) Usefulness of an indicator depends upon change in:

A) its colour         done clear

B) its physical state done clear

C) its temperature             done clear

D) its pressure done clear

question_answer 12) Acid present in vinegar is:

A) formic acid                  done clear

B) acetic acid done clear

C) sulphuric acid              done clear

D) nitric acid done clear

question_answer 13) Reaction of an acid with a base is:

A) decomposition             done clear

B) combination done clear

C) redox                           done clear

D) neutralization done clear

question_answer 14) Antacids contain:

A) weak base        done clear

B) weak acid done clear

C) strong base      done clear

D) strong acid done clear

question_answer 15) Which medicines are used for treating indigestion?

A) Antibiotic        done clear

B) Analgesic done clear

C) Antacids         done clear

D) Antiseptic done clear

question_answer 16) Which of the following is acidic in nature?

A) Apple juice      done clear

B) Soap solution done clear

C) Slaked lime                  done clear

question_answer 17)  .................. is present in sour milk-

A) Glycolic add                done clear

B) Lactic acid done clear

C) Citrus add       done clear

D) Tartaric acid done clear

question_answer 18)  .................. is the strongest add:

A) Nitric add       done clear

B) Malic add done clear

C) Formic add                  done clear

D) Lactic add done clear

question_answer 19) Sharp pain caused by an ant bite is due to:

A) malic acid                    done clear

B) nitric acid done clear

C) formic add       done clear

D) lactic add done clear

question_answer 20) Acid turns:

A) blue litmus red    done clear

B) red litmus blue done clear

C) blue litmus green          done clear

D) red litmus yellow done clear

question_answer 21) Which is not a property of an acid?

A) All acids have sour taste. done clear

B) All acids turn blue litmus red. done clear

C) All acids turn red litmus blue. done clear

D) All the acids give neutralisation reaction. done clear

question_answer 22) Bases:

A) have slippery feel         done clear

B) tastes sour done clear

C) turn blue litmus red      done clear

D) All these are correct done clear

question_answer 23) Acids are stored in glass container and not in metallic containers. Why?

A) Glass containers are transparent done clear

B) Glass containers are cheaper done clear

C) Metal containers are not easily available. done clear

D) Metals react with acids if acids are stored in metallic containers. done clear

question_answer 24) Which of the following is a neutralization reaction?

A) Sodium chloride + Water\[\to \] Sodium hydroxide + Hydrochloric acid done clear

B) Calcium carbonate + Water\[\to \] Calcium hydroxide + Carbon dioxide done clear

C) Sodium hydroxide + Hydrochloric add \[\to \]Sodium chloride + Water done clear

D) Copper sulphate + Zinc\[\to \] Zinc sulphate + Copper done clear

question_answer 25) Select the one that should be used for treating a person stung by an ant.

A) Sodium carbonate solution done clear

B) Water   done clear

C) Vinegar                        done clear

question_answer 26) ................ is present in grapes.

A) Malic add        done clear

B) Tartaric acid done clear

C) Acetic acid                   done clear

D) Citric acid done clear

question_answer 27) Disposal of factory wastes in water bodies has been found to be harmful to water plants and animals. To prevent this the factory owner should:

A) neutralize waste before disposal done clear

B) make the waste acidic before disposal done clear

C) make the waste basic before disposal done clear

D) All of the above are correct done clear

question_answer 28) Which of the following statements is correct?

A) Products of neutralization reaction are salt and water. done clear

B) Reactants of neutralization reaction are acid and alkali. done clear

C) Any neutralization reaction is an exothermic reaction. done clear

D) All the above are correct. done clear

question_answer 29) Which of the following statements is correct?

A) Hydrochloric acid turns red litmus to blue. done clear

B) Sodium hydroxide turns blue litmus to red. done clear

C) Both the above are correct. done clear

D) None of these is correct. done clear

question_answer 30) Which of the following statements is correct?

A) Indicator is a substance that shows different colors in acidic and basic solution. done clear

B) Turmeric stain on a white shut turns to red when it is washed with soap. done clear

C) Lime water is a solution of calcium hydroxide. done clear

question_answer 31) Which of the following statements is correct?

A) Acids are corrosive in nature. done clear

B) Excess of carbon dioxide in air can cause acid rain. done clear

C) Excess of hydrochloric acid in stomach causes indigestion. done clear

question_answer 32) A natural dye extracted from lichens and most commonly used as an indicator. What is its colour in distilled water?

A) Blue (b)                        done clear

B) Red done clear

C) Mauve              done clear

D) Colourless done clear

question_answer 33) ............... changes odour in acidic and basic medium and is used as an olfactory indicator.

A) Onion                          done clear

B) Vanilla done clear

C) Clove oil         done clear

D) All of these done clear

question_answer 34) Neutral substances are:

A) those substances which are slightly acidic or slightly basic in solution. done clear

B) those substances which do not change the colour of either red or blue litmus done clear

C) Both the above are correct done clear

D) None of the above is correct done clear

question_answer 35) Rain becomes acidic:

A) because excess of carbon dioxide present in air get dissolved in rain drops to form carbonic acid. done clear

B) oxides of nitrogen and sulphur present in air dissolve to form respective acids. done clear

D) None of these is correct done clear

question_answer 36) A base is a substance that

A) feels slippery done clear

C) reacts with metals to produce hydrogen gas done clear

D) and (c) done clear

question_answer 37) A neutralization reaction

A) includes an acid and a base    done clear

B) produces a salt done clear

C) forms water done clear

D) All of the above done clear

question_answer 38) Which among the following is organic weak acid?

A) Formic acid     done clear

C) Nitric acid       done clear

question_answer 39) Which among the given acids is the strongest acid?

A) Acetic acid       done clear

C) Formic acid                 done clear

D) Tannic acid done clear

question_answer 40) Which of the following is the weakest acid?

A) Citric           done clear

B) Sulphuric done clear

C) Hydrochloric                done clear

D) Nitric done clear

A) A\[\to \] (p), B\[\to \] (q), C\[\to \] (r), D\[\to \] (s) done clear

B) A\[\to \] (q), B\[\to \] (s), C\[\to \] (p), D\[\to \] (r) done clear

C) A\[\to \] (r), B\[\to \] (p), C\[\to \] (s), D\[\to \] (q) done clear

D) A\[\to \] (s), B\[\to \] (r), C\[\to \] (q), D\[\to \] (p) done clear

A)          A\[\to \] (s), B\[\to \] (q), C\[\to \] (p), D\[\to \] (r) done clear

B) A\[\to \] (r), B\[\to \] (s), C\[\to \] (q), D\[\to \] (p) done clear

C) A\[\to \] (s), B\[\to \] (r), C\[\to \] (p), D\[\to \] (q) done clear

D) A\[\to \] (p), B\[\to \] (q), C\[\to \] (r), D\[\to \] (s) done clear

A) A\[\to \] (s), B\[\to \] (p), C\[\to \] (q), D\[\to \] (r) done clear

B) A\[\to \] (s), B\[\to \] (q), C\[\to \] (r), D\[\to \] (p) done clear

C) A\[\to \] (s), B\[\to \] (q), C\[\to \] (p), D\[\to \] (r) done clear

D) A\[\to \] (r), B\[\to \] (q), C\[\to \] (p), D\[\to \] (s) done clear

A) A\[\to \] (s), B\[\to \] (q), C\[\to \] (p), D\[\to \] (r) done clear

B) A\[\to \] (r), B\[\to \] (q), C\[\to \] (p), D\[\to \] (s) done clear

C) A\[\to \] (q), B\[\to \] (r), C\[\to \] (p), D\[\to \] (s) done clear

D) A\[\to \] (r), B\[\to \] (q), C\[\to \] (s), D\[\to \] (p) done clear

question_answer 45) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage ? 1 Observe the flow chart given below and answer the questions that follow: \[\text{Magnesium+Oxygen}\xrightarrow{\text{heat}}\text{''A''}\xrightarrow{\text{Water}}\text{''B''}\xrightarrow[\text{solution}]{\text{Red litmus}}\text{''C''}\] "A" in this represents

A) magnesium oxide done clear

B) magnesium hydroxide done clear

C) both magnesium oxide and magnesium hydroxide done clear

D) none of these done clear

question_answer 46) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage ? 1 Observe the flow chart given below and answer the questions that follow: \[\text{Magnesium+Oxygen}\xrightarrow{\text{heat}}\text{''A''}\xrightarrow{\text{Water}}\text{''B''}\xrightarrow[\text{solution}]{\text{Red litmus}}\text{''C''}\] "B" in this represents

A) Magnesium                  done clear

B) Magnesium oxide done clear

C) Magnesium hydroxide done clear

question_answer 47) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage ? 1 Observe the flow chart given below and answer the questions that follow: \[\text{Magnesium+Oxygen}\xrightarrow{\text{heat}}\text{''A''}\xrightarrow{\text{Water}}\text{''B''}\xrightarrow[\text{solution}]{\text{Red litmus}}\text{''C''}\] "C" in it indicates that

A) Red litmus when added to "B", no change in colour occurs. done clear

B) Red litmus when added to "B" changes to blue. done clear

C) Red litmus when added to "B" changes to green. done clear

D) Red litmus when added to "B" it gives a colorless solution done clear

question_answer 48) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage ? 2 The reaction between an acid and a base is known as neutralization reaction. In this reaction salt and water are produced with evolution of heat. Salt is a product formed as a result of neutralization reaction. Name the salt formed by reaction of sodium hydroxide and hydrochloric acid.

A) sodium carbonate        done clear

B) sodium bicarbonate done clear

C) sodium chloride           done clear

D) sodium sulphate done clear

question_answer 49) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage ? 2 The reaction between an acid and a base is known as neutralization reaction. In this reaction salt and water are produced with evolution of heat. A neutralization reaction is:

A) an exothermic reaction done clear

B) endothermic reaction done clear

C) accompained by absorption of heat done clear

question_answer 50) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage ? 2 The reaction between an acid and a base is known as neutralization reaction. In this reaction salt and water are produced with evolution of heat. Which of the following is not an example of neutralization?

A) Taking antacid in case of acidity done clear

B) Treating acidic soil with quick lime done clear

C) Change in colour of blue litmus paper to red with acidic solution done clear

question_answer 51) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 3 Rahul and Manish went to a party Rahul ate too much fast food in the party and after returning home was complaining about the stomachache. Manish was worried about his condition. They went to doctor. Doctor told them not to get worried as this is due to indigestion of food and gave him some medicines. Which of the following acid present in our stomach helps in digestion?

A) Acetic acid done clear

B) Oxalic acid done clear

C) Hydrochloric acid done clear

question_answer 52) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 3 Rahul and Manish went to a party Rahul ate too much fast food in the party and after returning home was complaining about the stomachache. Manish was worried about his condition. They went to doctor. Doctor told them not to get worried as this is due to indigestion of food and gave him some medicines. Indigestion is caused by presence of excess of ........................... in the stomach?

A) food material   done clear

B) hydrochloric acid done clear

C) baking soda                 done clear

D) milk of magnesia done clear

question_answer 53) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 3 Rahul and Manish went to a party Rahul ate too much fast food in the party and after returning home was complaining about the stomachache. Manish was worried about his condition. They went to doctor. Doctor told them not to get worried as this is due to indigestion of food and gave him some medicines. The medicines that are used to relieve us of indigestion are generally called

A) antibiotic         done clear

B) analgesic done clear

C) antacid           done clear

D) antipyretic done clear

question_answer 54) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 3 Rahul and Manish went to a party Rahul ate too much fast food in the party and after returning home was complaining about the stomachache. Manish was worried about his condition. They went to doctor. Doctor told them not to get worried as this is due to indigestion of food and gave him some medicines. Which of the following is used as an antacid?

A) Acetic acid                   done clear

B) Sodium hydroxide done clear

question_answer 55) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 4 Indicators change their colour when added to a solution containing an acidic or a basic substance. Turmeric, litmus, China rose petals (Gudhal), etc., are some naturally occurring indicators. Naturally occurring indicator litmus

A) is extracted from lichens done clear

B) has available as red and blue litmus paper done clear

C) has purple colour in distilled water done clear

D) All the above are correct done clear

question_answer 56) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 4 Indicators change their colour when added to a solution containing an acidic or a basic substance. Turmeric, litmus, China rose petals (Gudhal), etc., are some naturally occurring indicators. Which of the following statements is correct?

A) Colour of litmus changes from blue to red in an acidic solution. done clear

B) Colour of litmus changes from red to blue in an acidic solution. done clear

C) Colour of litmus changes from pink to colourless in an acidic solution. done clear

D) Colour of litmus changes from colourless to pink in a basic solution. done clear

question_answer 57) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 4 Indicators change their colour when added to a solution containing an acidic or a basic substance. Turmeric, litmus, China rose petals (Gudhal), etc., are some naturally occurring indicators. Which of the following is correct about the indicator China rose?

A) It is a natural indicator. done clear

B) It gives green colour in an acidic solution. done clear

C) It gives magenta colour in a basic solution. done clear

question_answer 58) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 5 Consider the following substances and on that basis answer the following questions: Lemon juice, tomato juice, lime water, vinegar, sugar solution, solution of common salt. The number of acidic substances is:

A)  1                                 done clear

B)  2 done clear

C)  3                     done clear

D)  4 done clear

question_answer 59) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 5 Consider the following substances and on that basis answer the following questions: Lemon juice, tomato juice, lime water, vinegar, sugar solution, solution of common salt. The number of basic substances is:

C)  3                                 done clear

question_answer 60) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 5 Consider the following substances and on that basis answer the following questions: Lemon juice, tomato juice, lime water, vinegar, sugar solution, solution of common salt. The number of neutral substances:

question_answer 61) DIRECTIONS: The questions in this segment consists of two statements, one labeled as "Assertion A" and the other labeled as "Reason R". You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): Sulphuric acid is also known as oil of vitriol. Reason (R): It has oily appearance.

A) Both A and R are true and R is the correct explanation of A. done clear

B) Both A and R are true but R is not the correct explanation of A. done clear

C) A is true but R is false. done clear

D) A is false but R is true. done clear

question_answer 62) DIRECTIONS: The questions in this segment consists of two statements, one labeled as "Assertion A" and the other labeled as "Reason R". You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): Rain containing excess amount of acid is called acid rain. Reason (R): Air pollutants like carbon dioxide, sulphur dioxide, nitrogen oxides dissolve in water to form carbonic acid, sulphuric acid and nitric acid.

question_answer 63) DIRECTIONS: The questions in this segment consists of two statements, one labeled as "Assertion A" and the other labeled as "Reason R". You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): Sodium hydroxide is an alkali. Reason (R): All bases are alkalies.

question_answer 64) DIRECTIONS: The questions in this segment consists of two statements, one labeled as "Assertion A" and the other labeled as "Reason R". You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): Toothpaste neutralised the acid produced by fermentation of food particles in mouth. Reason (R): Toothpaste is alkaline in nature.

question_answer 65) DIRECTIONS: The questions in this segment consists of two statements, one labeled as "Assertion A" and the other labeled as "Reason R". You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): Sugar is a neutral substance. Reason (R): A sugar solution turns red litmus blue.

question_answer 66) DIRECTIONS: The questions in this segment consists of two statements, one labeled as "Assertion A" and the other labeled as "Reason R". You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): Acids are sour in taste. Reason (R): Bases are soapy to touch and bitter in taste.

question_answer 67) DIRECTIONS: Read the following two statements carefully and choose the correct options. (i) Orange juice turns blue litmus red (ii) Sting of an ant contains acetic acid

A) Statement (i) is correct while statement (ii) is incorrect done clear

B) Statement (ii) is correct while statement (i) is incorrect. done clear

C) Both statements are correct done clear

D) Both statements are incorrect. done clear

question_answer 68) DIRECTIONS: Read the following two statements carefully and choose the correct options. (i) Baking soda is a mild base that is used in toothpastes and mouthwashes to neutralize acids, which can produce unpleasant odours. (ii) An alkali is a water soluble acid.

question_answer 69) DIRECTIONS: Read the following two statements carefully and choose the correct options. (i) All salts are neutral in nature. (ii) A solution of sodium chloride salt in water does not change the colour of any litmus paper.

question_answer 70) DIRECTIONS: Read the following two statements carefully and choose the correct options. (i) Alkalies are sour to taste. (ii) Mineral acids change to organic acids on addition of water.

question_answer 71) DIRECTIONS: On the basis of following diagram/ picture answer the questions given below: Which of the following is the source of tartaric acid.

question_answer 72) DIRECTIONS: On the basis of following diagram/ picture answer the questions given below: Which of the following will change red litmus paper to blue?

question_answer 73) A blue litmus paper was first dipped I dilute hydrochloric acid and then in dilute sodium hydroxide solution. It was observed that the colour of the litmus paper:

A) changed to red done clear

B) changed first to red and then to blue done clear

C) changed blue to colourless done clear

D) remained blue in both solutions. done clear

question_answer 74) If you perform an experiment bare handed and you realise that your palm has become slippery and slimy. The most probable reason for this is that you have dropped:

A) sodium hydroxide on your hands. done clear

B) hydrochloric acid on your hands. done clear

C) sodium chloride on your hands. done clear

question_answer 75) To test a solution in container 'A.' You dipped the filter paper in this solution and then in lime water. The colour of filter paper after dipping in lime water becomes brownish red. It shows that the solution in container 'A' was:

A) Red litmus solution      done clear

B) Methyl red solution done clear

C) Turmeric solution done clear

D) Phenolphthalein solution done clear

question_answer 76) Which is responsible for the damaging effects caused by acid rain?

A) Carbonic acid              done clear

C) Nitric acid                    done clear

question_answer 77) You dissolved a sample, in distilled water and then added a drop of this solution to a test-tube containing blue litmus solution which changes to red. It shows that the sample given to you is of:

A) soap                             done clear

B) tomato juice done clear

C) baking soda                 done clear

D) sugar done clear

question_answer 78) When few drops of phenolphthalein are added to sample 'A' it turned pink. To this pink coloured solution we added a few drops of sample 'B'. With continuous stirring the pink colour disappears. Samples 'A' and 'B' are:

A) sample 'A' is acidic and sample 'B' is basic. done clear

B) sample 'A' is basic and sample 'B' is acidic. done clear

C) sample 'A' is basic and sample 'B' is neutral. done clear

D) sample 'A' is acidic and sample 'B' is neutral. done clear

question_answer 79) You are provided with two solutions 'X' and 'Y?. The colour of turmeric stains on your clothes on coming in contact with solution 'X' changes to brick red and when in contact with solution 'Y' changes to yellow. The solution 'X' and 'Y' provided to you are respectively:

A) Soap solution and lemon juice done clear

B) Lemon juice and soap solution done clear

C) Lemon juice and vinegar done clear

D) Soap solution and sugar solution done clear

question_answer 80) Following observation were recorded upon performing experiments with sample 'A' and sample 'B'. (i) When 2-3 drops of phenolphthalein are added to sample 'A' it becomes pink. (ii) When equal quantities of two samples are added in a test-tube, the test-tube becomes hot.

A) sample 'A' is basic       done clear

B) sample 'B' is acidic done clear

C) (ii) observation confirms neutralisation done clear

question_answer 81) ............... is an acid-base indicator, its colour is yellow in basic medium and pink in acidic medium.

A) Phenolphthalein done clear

B) Methyl orange done clear

C) Litmus done clear

D) Both (a) and (b) are correct done clear

question_answer 82) ............... is used to neutralize the acidic effect of ant bite by rubbing it at the point of ant bite.

A) Moist baking soda        done clear

B) Calamine solution done clear

C) Both (a) and (b)           done clear

D) Calcium carbonate done clear

question_answer 83) ............... is used to treat a soil that is acidic and min which plants do not grow well.

A) Quicklime done clear

C) Calcium oxide done clear

D) Any one of (a), (b) or (c) done clear

question_answer 84) Salts are compounds:

A) having a bitter taste done clear

B) having a sour taste done clear

C) obtained as a result of neutralization reaction between acid and base. done clear

question_answer 85) Many salts absorb water (moisture) from the atmosphere. This property is called

A) hydration       done clear

B) dehydration done clear

C) crystallization               done clear

D) decantation done clear

question_answer 86) The substances which form hydronium ions \[\left( {{\text{H}}_{\text{3}}}{{\text{O}}^{\text{+}}} \right)\] in water are called

A) acids          done clear

B) bases done clear

C) alkalies                         done clear

question_answer 87) The compounds which produce hydroxyl ions\[\text{(O}{{\text{H}}^{\text{-}}}\text{)}\] in water are called

A) alkalies                         done clear

C) acids                            done clear

question_answer 88) Metallic oxides dissolve in water to form

A) acidic solution             done clear

B) neutral solution done clear

C) basic solution               done clear

question_answer 89) Non-metallic oxides react with water to form

A) alkaline solution           done clear

B) acidic solution done clear

C) neutral solution            done clear

question_answer 90) A solution turns red litmus blue, its pH is likely to be

A)  1                                 done clear

B)  4 done clear

C)  5                                 done clear

D)  10 done clear

question_answer 91) The acid present in tea is:

A) tannic  done clear

B) lactic done clear

C) tartaric                         done clear

D) citric done clear

question_answer 92) Acid reacts with metal to form:

A)  \[\text{salt+C}{{\text{O}}_{\text{2}}}\]                 done clear

B)  salt + water done clear

C)  \[\text{salt+}{{\text{O}}_{\text{2}}}\]                                done clear

D)  \[\text{salt+}{{\text{H}}_{\text{2}}}\] done clear

question_answer 93) Manisha took a little bit of soil from her garden and mixed it with water. When she dipped a blue litmus in it, the litmus turned red- By adding which of the following to her garden will she get better plant growth?

A) Hydrochloric acid        done clear

C) Water               done clear

D) Salt done clear

question_answer 94) Common name of \[{{\text{H}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}\] is:

A) oil of vitriol      done clear

B) muriatic acid done clear

C) blue vitriol       done clear

D) green vitriol done clear

question_answer 95) Common name of copper sulphate is:

A) chalk                            done clear

B) quicklime done clear

C) nitre                             done clear

D) blue vitriol done clear

question_answer 96) The waste from a paper factory contains high amount of hydrochloric acid. How should we treat the waste, before disposal, to make it safe?

A) Treat it with chemicals containing sodium hydroxide done clear

B) Treat it with chemicals containing sulphuric acid done clear

C) Treat it with chemicals containing sodium chloride done clear

D) Treat it with pure hydrochloric acid done clear

question_answer 97) Read the following statements: (i) It is a reaction between an acid and a base. (ii) Salt and water are produced in this reaction. (iii) It is an exothermic reaction. Which reaction is being referred to?

A) Displacement reaction done clear

B) Neutralization reaction done clear

C) Redox reaction done clear

D) Decomposition reaction done clear

A)  (i) & (iii)                     done clear

B)  (ii) & (iv) done clear

C)  (i), (ii) & (iii)               done clear

D)  (i), (iii) & (iv) done clear

question_answer 99) The two types of litmus paper are:

A) blue and red    done clear

B) blue and yellow done clear

C) red and green               done clear

D) yellow and red done clear

question_answer 100) In acids, methyl orange turns:

A) yellow                          done clear

B) green done clear

C) red                   done clear

D) white done clear

question_answer 101) In bases, methyl orange turns:

A) green                            done clear

B) black done clear

C) red                               done clear

D) yellow done clear

question_answer 102) Phenolphthalein turns_______ in acidic and neutral solutions.

A) colourless       done clear

B) pink done clear

D) green done clear

question_answer 103) Lime water is a solution of:

A)  \[\text{Ca(OH}{{\text{)}}_{\text{2}}}\]in water     done clear

B)  \[\text{CaC}{{\text{l}}_{\text{2}}}\] in water done clear

C)  \[\text{NaOH}\] in water        done clear

D)  \[\text{NaCl}\] in water done clear

question_answer 104) Silver and gold are purified with:

A) nitric acid      done clear

B) \[\text{HCl}\] done clear

C) acetic acid      done clear

D) sulphuric acid done clear

question_answer 105) Soluble bases are called:

A) salts                             done clear

B) acids done clear

C) alkalies             done clear

D) All the three done clear

question_answer 106) Caustic soda is the common name for:

A)  \[\text{Mg(OH}{{\text{)}}_{\text{2}}}\]                  done clear

B)  \[\text{KOH}\] done clear

C)  \[\text{Ca(OH}{{\text{)}}_{\text{2}}}\]                  done clear

D)  \[\text{NaOH}\] done clear

question_answer 107) Calcium hydroxide (slaked lime) is used in:

A) plastics and dyes          done clear

B) fertilizers done clear

C) antacid            done clear

D) whitewashing done clear

A) (A) \[\to \] (p), (B) \[\to \] (q), (C) \[\to \] (r), (D) \[\to \] (s) done clear

B) (A) \[\to \] (q), (B) \[\to \] (r), (C) \[\to \] (p), (D) \[\to \] (s) done clear

C) (A) \[\to \] (r), (B) \[\to \] (s), (C) \[\to \] (q), (D) \[\to \] (p) done clear

D) (A) \[\to \] (s), (B) \[\to \] (p), (C) \[\to \] (q), (D) \[\to \] (r) done clear

A) (A) \[\to \] (s), (B) \[\to \] (q), (C) \[\to \] (r), (D) \[\to \] (p) done clear

B) (A) \[\to \] (q), (B) \[\to \] (s), (C) \[\to \] (p), (D) \[\to \] (r) done clear

C) (A) \[\to \] (r), (B) \[\to \] (q), (C) \[\to \] (p), (D) \[\to \] (s) done clear

D) (A) \[\to \] (s), (B) \[\to \] (q), (C) \[\to \] (p), (D) \[\to \] (r) done clear

A) (A) \[\to \] (s), (B) \[\to \] (p), (C) \[\to \] (q), (D) \[\to \] (r) done clear

C) (A) \[\to \] (r), (B) \[\to \] (p), (C) \[\to \] (s), (D) \[\to \] (q) done clear

D) (A) \[\to \] (s), (B) \[\to \] (r), (C) \[\to \] (q), (D) \[\to \] (p) done clear

question_answer 111) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 1 The rain which contains a higher level of acid than normal is called acid rain. Acidic gases like sulphur dioxide, nitrogen dioxide and carbon dioxide which are released as pollutants during the burning of various types of faels dissolve in rain drops and when these rain drops fall as rain on earth, we call it acid rain. Nonmetallic oxides react with water to form:

A) acids                done clear

C) salt                               done clear

question_answer 112) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 1 The rain which contains a higher level of acid than normal is called acid rain. Acidic gases like sulphur dioxide, nitrogen dioxide and carbon dioxide which are released as pollutants during the burning of various types of faels dissolve in rain drops and when these rain drops fall as rain on earth, we call it acid rain. \[\text{C}{{\text{O}}_{\text{2}}}\] dissolves in a water to form:

A)  \[\text{C+}{{\text{H}}_{\text{2}}}+{{\text{O}}_{\text{2}}}\]               done clear

B)  \[\text{C}{{\text{H}}_{\text{4}}}\] done clear

C)  \[\text{CO}\]                          done clear

D) carbonic acid done clear

question_answer 113) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 1 The rain which contains a higher level of acid than normal is called acid rain. Acidic gases like sulphur dioxide, nitrogen dioxide and carbon dioxide which are released as pollutants during the burning of various types of faels dissolve in rain drops and when these rain drops fall as rain on earth, we call it acid rain. Sulphuric acid is formed when ____ reacts with water.

A)  \[\text{S}{{\text{O}}_{\text{2}}}\]                                      done clear

B)  S done clear

C)  \[\text{S}{{\text{O}}_{\text{3}}}\]             done clear

D)  \[{{\text{O}}_{\text{2}}}\] done clear

question_answer 114) DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 1 The rain which contains a higher level of acid than normal is called acid rain. Acidic gases like sulphur dioxide, nitrogen dioxide and carbon dioxide which are released as pollutants during the burning of various types of faels dissolve in rain drops and when these rain drops fall as rain on earth, we call it acid rain. What is the main cause of acid rain?

A) Pollution done clear

B) Deforestation done clear

C) Excessive rains done clear

D) All factors are equally effective done clear

A) An acid                        done clear

B) A base done clear

C) Water                           done clear

A) Water               done clear

B) Salt done clear

C) Either A or B done clear

D) Either an acid or a base done clear

A) By the reaction of X and Y done clear

B) By dissolving X in water done clear

C) By dissolving Y in water done clear

D) Cannot be said done clear

A)  \[{{\text{H}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}\]                      done clear

B)  \[\text{HN}{{\text{O}}_{\text{3}}}\] done clear

C)  \[\text{KOH}\]                        done clear

D)  \[{{\text{H}}_{\text{2}}}\text{O}\] done clear

A) It turns pink done clear

B) It remains colorless done clear

C) It turns blue done clear

D) It turns red done clear

question_answer 121) DIRECTIONS: The questions in this segment consists of two statements, one labelled as ?Assertion A? and the other labelled as ?Reason R?. You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): Turmeric is a neutral indicator. Reason (R): Turmeric acquires orange colour in alkaline solution.

question_answer 122) DIRECTIONS: The questions in this segment consists of two statements, one labelled as ?Assertion A? and the other labelled as ?Reason R?. You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): Salts are the products of an acid- base reaction. Reason (R): Salt may be acidic or basic.

question_answer 123) DIRECTIONS: The questions in this segment consists of two statements, one labelled as ?Assertion A? and the other labelled as ?Reason R?. You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): Neutralization reaction is accompanied by evolution of heat. Reason (R): Neutralization reaction is a reaction between an acid and a base to form salt and water.

question_answer 124) DIRECTIONS: The questions in this segment consists of two statements, one labelled as ?Assertion A? and the other labelled as ?Reason R?. You are to examine these two statements carefully and decide if the Assertion A and Reason R are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below. Assertion (A): The substance which shows the nature of a solution as acidic or basic with the change in colour are called indicators. Reason (R): Red litmus turns blue in a solution containing vitamin 'C'.

question_answer 125) DIRECTIONS: Read the following three statements and choose the correct answer. (i) The salt formed by the neutralization of \[\text{NaOH}\] with \[\text{HCl}\] is basic in nature. (ii) Milk of magnesia contains magnesium hydroxide. (iii) Bases have pH from 1 to 7.

A) Statement (i) and (iii) are incorrect but (ii) is correct done clear

B) Statement (i) and (ii) are incorrect but (iii) is correct done clear

C) All statements are correct done clear

D) All statements are incorrect done clear

question_answer 126) DIRECTIONS: Read the following three statements and choose the correct answer. (i) Phenolphthalein is a natural indicator. (ii) Sodium carbonate is commonly known as caustic soda. (iii) Universal indicator is made up of a mixture of different dyes.

question_answer 127) DIRECTIONS: Read the following three statements and choose the correct answer. (i) If the soil is basic then compost is added to it to neutralize the basic nature of soil. (ii) China rose indicator changes colour to dark pink in acidic media and green in basic media. (iii) Tomato contains acetic acid.

A) Saponification             done clear

B) Acidification done clear

C) Neutralization              done clear

D) Both (b) and (c) done clear

A) Sodium hydroxide                               Sodium chloride done clear

B) Hydrochloric acid                                Sodium hydroxide done clear

C) Sodium hydroxide acid                                    Aluminum hydroxide done clear

D) Hydrochloric acid                                Sodium chloride done clear

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Acids, Bases and Salts Class 7 Extra Questions and Answers Science Chapter 5

September 8, 2020 by Prasanna

In this page, we are providing Acids, Bases and Salts Class 7 Extra Questions and Answers Science Chapter 5 pdf download. NCERT Extra Questions for Class 7 Science Chapter 5 Acids, Bases and Salts with Answers will help to score more marks in your CBSE Board Exams.

Class 7 Science Chapter 5 Extra Questions and Answers Acids, Bases and Salts

Extra Questions for Class 7 Science Chapter 5 Acids, Bases and Salts with Answers Solutions

Acids, Bases and Salts Class 7 Extra Questions Very Short Answer Type

Question 1. Give two examples of acidic substances. Answer: Lemon juice and vinegar.

Question 2. Give two examples of basic substances. Answer: Lime water and baking soda.

Question 3. What is the colour of litmus in distilled water? Answer: Mauve (purple) colour.

Question 4. Name some substances in which tartaric acid is found? Answer: Tamarind, grapes, unripe mangoes, etc.

Question 5. Which base is found in window cleaner? Answer: Ammonium hydroxide.

Question 6. Give an example of an antacid. Answer: Milk of magnesia.

Question 7. What makes the soil acidic? Answer: Excessive use of chemical fertilisers.

Question 8. Which acid is injected into our skin when an ant bites? Answer: Formic acid.

Question 9. What helps us to digest food? Answer: Hydrochloric acid helps us to digest food.

Question 10. Name two types of litmus papers. Answer: Red litmus paper and blue litmus paper.

Question 11. What colour does phenolphthalein give when the solution is basic? Answer: Pink

Question 12. What neutralises the basic nature of the soil? Answer: Acids released by organic matter neutralises the basic nature of the soil.

Question 13. When organic matter is added to the soil? Answer: If the soil is basic.

Question 14. What substance is used to treat the soil when it is too acidic? Answer: Bases like quick lime or slaked lime.

Question 15. What kills fish and other organism present in the water bodies? Answer: Releasing of factory wastes containing acids or bases.

Question 16. What is nature of salt? Answer: It may be acidic, basic or neutral in nature.

Question 17. What happens when an acidic solution is mixed with a basic solution? Answer: Both solution neutralises each other with the formation of salt, water and evolution of heat.

Question 18. What is neutralisation? Answer: The reaction between an acid and a base is called neutralisation.

Question 19. Name two natural indicator. Answer:

• Turmeric Question

Question 20. What is a neutral substance? Answer: The substance of solution which does not show any effect on litmus paper is called a neutral substance.

Question 21. What is an acid? Answer: The substance having sour taste is called an acid.

Question 22. What is a base? Answer: The substance having bitter taste and feels soapy on touching is called a base.

Acids, Bases and Salts Class 7 Extra Questions Short Answer Type

Question 1. Explain the terms acids and acidic. Answer: The substances that taste sour are called acids, such as curd, lemon juice, orange juice, vinegar, etc. The chemical nature of these substances are acidic.

Question 2. What are bases? What is their nature? Answer: The substances that taste bitter and feel soapy on touching are called bases; e.g., lime water, baking soda, washing soda, etc. The nature of these substances are basic.

Question 3. What are indicators? Answer: Indicators are special type of substances that are used to test whether a substance is acidic or basic. They change their colour when added to a solution containing an acidic or a basic substance. For example, turmeric, China rose petals, litmus, etc., are naturally occurring indicators.

Question 4. What is litmus? Answer: Litmus is the most commonly used natural indicator. It is extracted from lichens. It has mauve (purple) colour in distilled water when added to an acidic solution, it turns red and when added to a basic solution, it turns blue. It may be in the form of a solution or in the form of strips of paper called litmus paper, which are generally red and blue.

Question 6. Why do you rub baking soda or calamine solution when an ant bites us? Answer: When an ant bites, it inject formic acid into our skin, which is painful and may be very harmful sometimes. The effect of the acid can be neutralised by rubbing moist baking soda, i.e., sodium hydrogen carbonate or calamine solution containing zinc carbonate.

Question 7. How are the factory wastes neutralised? Answer: Many factory waste contain acids which kill fish and other organisms, if allowed to flow into the water bodies untreated. These wastes can be neutralised by adding basic substances to them.

Question 8. What is salt? Answer: Salt is a substance obtained from the neutralisation reaction of an acid and a base. Acid + Base ➝ Salt + Water + Heat Salt may be acidic, basic or neutral depending on whether the acids or bases used to make salts are weak or strong.

Question 9. What is meant by acid rain? Answer: The rain containing excess of acids is called acid rain. The rain becomes acidic because carbon dioxide, sulphur dioxide and nitrogen dioxide, which are released into the air as pollutants, dissolve in rain water to form carbonic acid, sulphuric acid and nitric acid respectively. Acid rain can cause damage to buildings, historical monuments, plants and animals.

Acids, Bases and Salts Class 7 Extra Questions Long Answer Type

Question 1. Explain the process of neutralisation with the help of an activity. Answer: When an acidic solution is mixed with a basic solution, both the solutions neutralise the effect of each other. The resulting solution is neither acidic nor basic. We can show the process of neutralisation with the help of an activity.

Fill one-fourth of a test tube with dilute hydrochloric acid. Note down its colour and also the colour of . phenolphthalein solution. Add 2-3 drops of the indicator to the acid. Shake the test tube gently. We observe that solution remains colourless. Add sodium hydroxide solution in the test tube drop by drop with continuous stirring till the pink colour just appears. Appearance of pink colour indicates that the neutralisation reaction has completed.

Question 2. What are the applications of neutralisation reaction in everyday life? Answer: Neutralisation helps us in many ways in our everyday life. Some of the applications are:

• Indigestion: When we suffer from acidity we take antacid to get relief. Antacid neutralises the effect of excessive acid.
• Ant bite: When an ant bites, moist baking soda solution or calamine solution is rubbed which neutralises the effect of acid injected into the skin when an ant bites.
• Soil treatment: Plants do not grow well when the soil is too acidic or too basic. When the soil is too acidic, it is treated with bases like quick lime or slaked lime and when it is basic, organic matter is added to it. Organic matter releases acids which neutralise the basic nature of the soil.
• Factory wastes: The factory wastes contain acids, they are harmful for water bodies. To neutralise these wastes, basic substances are added to them.

Acids, Bases and Salts Class 7 Extra Questions HOTS

Question 1. If we add dilute sulphuric acid to lime water, what will happen to the reaction mixture? Answer: The reaction mixture will become hot due to neutralisation reaction between sulphuric acid and lime water.

Question 2. In a reaction given below, how can we get solid sodium chloride from its solution? Hydrochloric acid + Sodium hydroxide ➝ Sodium chloride + Water Answer: Through the process of evaporation we can get solid sodium chloride from its solution. We must evaporate the water in a container over a burner until all the water from the mixture evaporates.

Question 3. Shweta took a little sodium hydroxide in a beaker and dipped a red litmus paper into it. She observed red litmus paper turned blue. She took dilute hydrochloric acid in the same beaker and dipped a blue litmus paper into it. The blue litmus paper did not turn red. Why? Answer: Shweta took dilute hydrochloric acid in the same beaker containing sodium hydroxide solution. Mixing of base into acid forms salt which is neutral and does not change colour of either blue or red litmus paper.

Question 4. Why litmus is better natural indicator than other natural indicator? Answer: Litmus give wide range of colour change from weak acid to strong acid and from weak base to strong base. Other natural indicator, on the other hand, do not show a wide colour change.

Question 5. Is it advisable to drink lemonade during indigestion? Why? Answer: No it is not advisable to drink lemonade during indigestion because it is acidic in nature. Too much acidity in stomach causes indigestion. Drinking lemonade may worsen the condition.

Acids, Bases and Salts Class 7 Extra Questions Value Based (VBQs)

During performing an experiment on neutralisation reaction, Ravi took about 100 mL of sodium hydroxide solution and pour approximately the same amount of concentrated hydrochloric acid to it. He observed a very vigorous reaction with evolution of large amount of heat. When he dipped litmus paper into the solution it turned red. He was surprised with the result though he had read all the instructions and precautions given to him by his teacher. (a) What was the expected result of the experiment? (b) What went wrong in the experiment performed by Ravi? (c) Why Ravi observed a very vigorous reaction with evolution of large amount of heat when he added concentrated hydrochloric acid to sodium hydroxide? (d) What value of Ravi is shown here? Answer: (a) It was expected that the solution form will be neutral and would not change colour of the litmus. (b) Ravi added concentrated hydrochloric acid instead of dilute hydrochloric acid. This mistake can prove very dangerous. (c) Hydrochloric acid is a strong acid and sodium hydroxide is a strong base themselves to produce enough heat when mixed together. In addition to this, Ravi used concentrated form of this acid which can even cause burns. (d) Ravi showed carelessness over here by not reading the instructions and precautions carefully before performing an experiment.

Question 2. Class VII students went for an educational trip to see how various industries and human settlements around river Yamuna, in Delhi, is polluting it deliberately. They saw that factory wastes and municipal wastes are dumped into it untreated. They thought of spreading an awareness programme. They even wrote to Municipal Corporation of the state suggesting ways to reduce this kind of pollution. (a) How factory or domestic wastes affect the quality of river? (b) How the process of neutralisation is effective in changing some of the quality of water? (c) Suggest any two ways to reduce pollution of river Yamuna. (d) Why is it important to check river pollution? (e) What methods will you adopt to spread awareness against river pollution? Answer: (a) Factory or domestic waste changes colour, turbidity, acidity or basicity, temperature, microbial growth, etc., of the water. (b) If the river water is too acidic or basic, it can affect the aquatic life. So by neutralising the pollutants before discharging into the river can at least change water quality to neutral. (c) Pollution of river Yamuna can be reduced largely by making the people aware that how can they contribute in their own level to control water pollution and giving strict guidelines to industries situated near river bank to treat their waste suitably before discharging it into the river. (d) It is important to check river pollution because they are our lifeline. We all are dependent mainly on river water for various activities like drinking water, irrigation, fishing, etc. Pollution of river water also affect the aquatic life. (e) We will make poster, do some street dramas, will write an article in newspaper or social sites and most important will follow the rules to minimise water pollution by ourselves.

Acids, Bases and Salts Class 7 Extra Questions and Answers Science Chapter 5

Acids, Bases and Salts Class 7 Extra Questions and Answers Science Chapter 5 PDF are solved by experts and will guide students in the right direction. Students can get how to tackle different questions easily by solving the Extra Questions for Class 7 Science Question bank on a regular basis.

Class 7 Science Chapter 5 Extra Questions and Answers Acids, Bases and Salts

Extra Questions for Class 7 Science Chapter 5 Acids, Bases and Salts with Answers

Acids, Bases and Salts Class 7 Extra Questions Very Short Answer Type

Question 1. What is common in the sour-tasting substances? Answer: They contain acids.

Question 2. Name two naturally occurring indicators. Answer: Turmeric, litmus.

Question 3. Name some common acids and bases and their sources. Answer:

Question 4. What are the various colours of litmus paper? Answer: Red and blue.

Question 5. What is the colour of litmus in distilled water? Answer: Mauve (purple).

Question 6. Why acids and bases should be handled with care? Answer: Great care should be taken while handling laboratory acids and bases because these are corrosive in nature, irritating and harmful to skin.

Question 7. How is the soil treated when it becomes too acidic? Answer: When the soil becomes too acidic, it is treated with bases like quick lime (calcium oxide) or slaked lime (calcium hydroxide).

Question 8. What is done if soil becomes too basic? Answer: If the soil becomes too basic, organic matter is added to it. Organic matter releases acids which neutralises the basic nature of the soil.

Question 9. Name one antacid. Answer: Milk of magnesia, which contains magnesium hydroxide.

Question 10. What does calamine solution contain? Answer: Zinc Carbonate.

Acids, Bases and Salts Class 7 Extra Questions Short Answer Type 1

Question 1. How is lime water prepared? Answer: To prepare limewater, some lime (chuna) is dissolved in water. The solution is stirred and is left for some time. Later a little clear solution from the top is decanted. This is lime water.

Question 2. How does rain become acidic? Answer: The rain becomes acidic because carbon dioxide, sulphur dioxide and nitrogen dioxide (which are released into the air as pollutants) dissolve in raindrops to form carbonic acid, sulphuric acid and nitric acid respectively, making rainwater acidic.

Question 3. How is an ant’s sting relieved? Answer: When an ant bites, it injects an acidic liquid into the skin. The effect of the sting can be neutralised by rubbing moist baking soda (sodium hydrogen carbonate) or calamine solution which contain zinc carbonate as both of these are bases.

Acids, Bases and Salts Class 7 Extra Questions Short Answer Type 2

Question 1. What should be done to neutralise acidic factory wastes and why? Answer: The wastes of many factories contain acids. If they are allowed to flow into the water bodies, the acids will kill fish and other organisms. The factory wastes are, therefore, neutralised by adding basic substances.

Acids, Bases and Salts Class 7 Extra Questions Long Answer Type

Question 1. Write a brief note on litmus? Answer: The most commonly used natural indicator is litmus. It is extracted from lichens. It has a mauve (purple) colour in distilled water. When added to an acidic solution, it turns red and when added to a basic solution, it turns blue. It is available in the form of a solution, or in the form of strips of paper, known as litmus paper. Generally, it is available as red and blue litmus paper.

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Extra Questions for Class 7 Science Chapter 5 Acids Bases and Salts

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Table of Contents

‘Extra questions for Class 7 Science’ refer to additional practice questions and exercises that may go beyond the standard curriculum provided in textbooks. These questions are designed to provide students with more opportunities to practice and reinforce their understanding of concepts taught in Class 7.

These extra questions cover a wide range of topics, difficulty levels, and question formats, allowing students to challenge themselves and gain a deeper insight into the subject. They are particularly valuable for students who seek to excel in their subject, as they provide the chance to explore different question-answer approaches and solidify their grasp of fundamental principles.

Acids Bases and Salts Class 7 Science Extra Questions

Chapter list, latest chapter list (2023-24).

Chapter 1 Nutrition in Plants Chapter 2 Nutrition in Animals Chapter 3 Heat Chapter 4 Acids, Bases and Salts Chapter 5 Physical and Chemical Changes Chapter 6 Respiration in Organisms Chapter 7 Transportation in Animals and Plants Chapter 8 Reproduction in Plants Chapter 9 Motion and Time Chapter 10 Electric Current and Its Effects Chapter 11 Light Chapter 12 Forests: Our Lifeline Chapter 13 Wastewater Story

Old Chapter List

Chapter 1 Nutrition in Plants Chapter 2 Nutrition in Animals Chapter 3 Fibre to Fabric Chapter 4 Heat Chapter 5 Acids, Bases and Salts Chapter 6 Physical and Chemical Changes Chapter 7 Weather, Climate and Adaptations of Animals to Climate Chapter 8 Winds, Storms and Cyclones Chapter 9 Soil Chapter 10 Respiration in Organisms Chapter 11 Transportation in Animals and Plants Chapter 12 Reproduction in Plants Chapter 13 Motion and Time Chapter 14 Electric Current and Its Effects Chapter 15 Light Chapter 16 Water: A Precious Resource Chapter 17 Forests: Our Lifeline Chapter 18 Wastewater Story

Significance of Extra Questions in CBSE Class 7 Science

Strengthening Core Concepts

• Solidifying Fundamental Principles : Extra questions provide opportunities to reinforce core scientific concepts introduced in the classroom. This reinforcement is crucial for establishing a robust foundation and building a comprehensive understanding of scientific principles.
• Enhancing Retention and Application : Practicing extra questions helps students remember and apply scientific theories more effectively. The act of solving varied problems aids in grasping the practical applications of learned theories.

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• Developing Critical Analysis Skills : Extra questions challenge students to analyze scientific scenarios, fostering critical thinking and analytical skills. This ability to critically evaluate information is essential for drawing accurate conclusions in scientific investigations.
• Promoting Curiosity and Exploration : Extra questions often present unique scenarios that encourage students to explore beyond textbook content. This curiosity-driven exploration nurtures a deeper curiosity about the natural world and sparks an enthusiasm for scientific inquiry.

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Textbook Supplements and Workbooks

• Exploring Additional Exercises: Many textbooks include supplementary exercises at the end of each chapter. These exercises often provide extra questions that delve deeper into the concepts covered in the chapter. Utilize these resources to reinforce your understanding and gain more practice.
• Enhancing Practice Through Worksheets: Workbooks specifically designed for practice are a treasure trove of extra questions. These worksheets are curated to challenge your knowledge and offer a wide variety of problems that span the curriculum.

Note : You can also purchase workbook from our website. It contains various questions for practice.

Incorporating Extra Questions into Regular Practice

• Establishing a Structured Study Plan: Dedicate specific time slots for practicing extra questions. By integrating these questions into your regular study routine, you create a consistent and effective practice schedule.
• Balancing Between Regular Studies and Practice: While extra questions are important, ensure they complement your regular studies. Strike a balance between learning new concepts and reinforcing them through extra practice.

Monitoring Progress and Identifying Weak Areas

• Regular Self-Assessment: Periodically evaluate your performance on extra questions. This self-assessment helps you gauge your understanding of different topics and track your improvement over time.
• Identifying Areas that Require More Focus: Use your self-assessment to pinpoint areas where you face difficulties. By identifying weak points, you can target those concepts for further study and practice.

Seeking Assistance and Clarification

• Consulting Teachers or Peers for Doubts: If you encounter challenges while practicing extra questions, don’t hesitate to seek guidance from your teachers or peers. They can provide explanations and insights that clarify your understanding.
• Resolving Misunderstandings Promptly: Address misunderstandings or misconceptions as soon as they arise. Clearing doubts ensures that you build a solid foundation and prevent confusion from persisting.

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• NCERT Exemplar
• NCERT Exemplar Class 7
• Class 7 Science
• Chapter 5 Acids Bases And Salts

NCERT Exemplar Solutions Class 7 Science Chapter 5 Acids Bases and Salts

NCERT Exemplar solutions for Class 7 Acids, Bases and Salts are designed in such a way that students will obtain detailed knowledge of the topics covered in the NCERT textbooks. They can solve these solutions regularly to practise well and score good marks in the annual exam.

These Exemplar Solutions for Class 7 Science have different types of questions, such as multiple-choice questions, indicator identification questions, questions on daily life examples, short answer questions and descriptive answer questions.

Download the PDF of NCERT Exemplar for Class 7 Science Chapter 5 – Acids, Bases and Salts

Importance of NCERT Exemplar for Class 7 Science Chapter 5 Acids, Bases and Salts

These exemplar solutions cover questions on the difference between acids, bases and salts, indicators, litmus paper test, neutralisation and daily life explanations. NCERT Exemplar Solutions for Class 7 Chapter 5 has answers and explanations to 11 multiple-choice questions, answers to 3 very short answer questions, 5 short answer questions, and 7 long questions.

Topics Covered in NCERT Exemplar for Class 7 Science Chapter 5

5.1 – Acids and Bases

5.2 – Natural Indicators Around Us

5.3 – Neutralisation

5.4 – Neutralisations in Everyday Life.

Access Answers of NCERT Exemplar for Class 7 Science Chapter 5 – Acids, Bases and Salts

Multiple-choice questions.

1. The correct way of making a solution of acid in water is to

(a) add water to acid.

(b) add acid to water.

(c) mix acid and water simultaneously.

(d) add water to acid in a shallow container.

The answer is (b) add acid to water.

Explanation:

If we add water to acid, it will be an exothermic reaction which will produce a lot of heat which may lead to an explosion. Hence, water should be added to the acid.

2. Products of a neutralisation reaction are always

(a) an acid and a base.

(b) an acid and a salt.

(c) salt and water.

(d) a salt and a base.

The answer is (c) salt and water.

3. Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed

(a) Yellow in both acid and base.

(b) Yellow in acid and red in the base.

(c) Pink in acid and yellow in the base.

(d) Red in acid and blue in the base.

The answer is (b) Yellow in acid and red in the base.

Turmeric paste is yellow in colour, and it is acidic in nature hence it remains yellow in acid, whereas it is converted to red due to neutralization by the base.

4. Phenolphthalein is a synthetic indicator, and its colours in acidic and basic solutions, respectively, are

(a) red and blue.

(b) blue and red.

(c) pink and colourless.

(d) colourless and pink

The answer is (d) colourless and pink

5. When the soil is too basic, plants do not grow well in it. To improve its quality what must be added to the soil?

(a) Organic matter

(b) Quick lime

(c) Slaked lime

(d) Calamine solution

The answer is (a) Organic matter

Organic matter is added to basic soil to neutralize its base, which improves its quality.

6. ‘Litmus’, a natural dye, is an extract of which of the following?

(a) China rose (Gudhal)

(b) Beetroot

(d) Blueberries (Jamun)

The answer is (c) Lichen

7. A neutralisation reaction is a

(a) physical and reversible change.

(b) a physical change that cannot be reversed.

(c) chemical and reversible change.

(d) the chemical change that cannot be reversed.

The answer is (d) chemical change that cannot be reversed.

It is a chemical reaction where acid and base react with each other quantitatively. Neutralization is an irreversible process.

8. A solution changes the colour of the turmeric indicator from yellow to red. The solution is

(c) neutral

(d) either neutral or acidic

The answer is (a) basic

Turmeric is acidic in nature hence it is converted to red due to neutralization by the base.

9. Which of the following set of substances contain acids?

(a) Grapes, lime water

(b) Vinegar, soap

(c) Curd, milk of magnesia

(d) Curd, vinegar

The answer is (d) Curd, vinegar

Curd contains lactic acid, and vinegar contains acetic acid.

10. On adding the phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution?

(b) Either acidic or basic

(c) Either acidic or neutral

(d) Either basic or neutral

The answer is (c) Either acidic or neutral

The colour of the phenolphthalein indicator will not change with an acidic or neutral solution.

11. Which of the following is an acid-base indicator?

(a) Vinegar

(b) Lime water

(c) Turmeric

(d) Baking soda

The answer is (c) Turmeric

Turmeric will be yellow in the acidic solution and red in the basic solution.

Very Short Answer Questions

12. Look at the given reaction.

Hydrochloric acid + Sodium hydroxide (base) → Sodium chloride (salt) + Water

Sodium chloride formed in this reaction remains in solution form. Can we get solid sodium chloride from this solution? Suggest a method (if any).

Sodium chloride is soluble in water hence we get a solution of sodium chloride. We can get solid sodium chloride by an evaporation method.

13. State whether the following statements are true or false. Correct the false statements.

(a) All substances are either acidic or basic.

(b) A compound, if acidic, will turn all indicators red.

(c) Lime water turns red litmus blue.

(d) Common salt dissolved in water turns blue litmus red.

(e) Phenolphthalein is a natural indicator.

(f) Calamine can be used to treat ant’s sting.

(g) Lemon water is basic in nature.

• False- Substance can be acidic, basic or neutral in nature
• False- Acids do not turn all indicators red.
• False- The colour of the litmus paper will not change at all
• False- Phenopthalein is a man-made indicator
• False- Lemon water is acidic in nature

14. Paheli is suffering from indigestion due to acidity. Is it advisable to give her orange juice in this situation, and why?

No, Orange juice is not advised because orange juice is acidic in nature.

Short Answer Questions

15. Look at Figure 5.1, which shows solutions taken in test tubes A, B, C and D. What colour is expected when a piece of red litmus paper is dropped in each test tube? The nature of the solutions is given in the table for your help.

16. While playing in a park, a child was stung by a wasp. Some elders suggested applying the paste of baking soda and other lemon juice as the remedy. Which remedy do you think is appropriate and why?

Wasp releases a liquid substance into the body when its stings. This liquid will be acidic in nature hence baking soda should be applied as a remedy, and adding lemon juice will increase the pain and redness.

17. Form a sentence using the following words – baking soda, ant bite, moist, effect, neutralised, rubbing.

The effect of an ant bite can be neutralised by rubbing moist baking soda.

18. Match the substances in Column I with those in Column II.

19. Fill in the blanks in the following sentences

(a) Lemon juice and vinegar taste ___________ because they contain ___________.

(b) Turmeric and litmus are _________ acid-base indicators.

(c) Phenolphthalein gives _________ colour with lime water.

(d) When an acidic solution is mixed with a basic solution, they _________ each other forming _________ and water.

(a) Lemon juice and vinegar taste sour because they contain acids .

(b) Turmeric and litmus are natural acid-base indicators.

(c) Phenolphthalein gives pink colour with lime water.

(d) When an acidic solution is mixed with a basic solution, they neutralize each other forming salt

Long Answer Questions

20. Boojho, Paheli and their friend Golu were provided with a test tube, each containing China rose solution, which was pink in colour. Boojho added two drops of solution ‘A’ in his test tube and got a dark pink colour. Paheli added 2 drops of solution ‘B’ to her test tube and got green colour. Golu added 2 drops of solution ‘C’ but could not get any change in colour. Suggest the possible cause for the variation in their results.

Since solution A turns China rose colour to dark pink hence Solution A is an acidic solution. solution B turns China rose colour to green colour hence Solution B is a basic solution. Since Solution C did not change the colour of china rose Solution, it is a neutral solution.

21. Fill in the crossword given as Figure 5.2 with the help of the clues provided.

(2) The solution which does not change the colour of either red or blue litmus.

(4) Phenolphthalein gives pink colour in this type of solution.

(7) Colour of blue litmus in lemon juice.

(1) It is used to test whether a substance is acidic or basic.

(3) It is a natural indicator and gives a pink colour in a basic solution.

(5) Nature of ant’s sting.

(6) It is responsible for the increase in temperature during a neutralisation reaction.

22. A farmer was unhappy because of his low crop yield. He discussed the problem with an agricultural scientist and realised that the soil of his field was either too acidic or too basic. What remedy would you suggest the farmer to neutralise the soil?

If the soil is too acidic, it is treated with bases such as quick lime (calcium oxide) or slaked lime (calcium hydroxide). If the soil is too basic, organic matter is added to it. Organic matter releases acids which neutralise the basic nature of the soil.

23. You are provided with four test tubes containing sugar solution, baking soda solution, tamarind solution, and salt solution. Write down the activity to find the nature (acidic/basic/neutral) of each solution.

Add blue litmus solution and then red litmus solution for the test tubes containing sugar solution, baking soda solution, tamarind solution, salt solution. One can observe the colour changes to find the nature of each of them. It is as follows.

Sugar and salt solution is neutral as there is no colour change

Baking soda turns red litmus to blue and it is a basic solution.

Tamarind solution turns blue litmus to red and it is acidic in nature

24. You are provided with three test tubes A, B and C as shown in Figure 5.3, with different liquids. What will you observe when you put

(a) a piece of blue litmus paper in each test tube.

(b) a piece of red litmus paper in each test tube.

(c) a few drops of phenolphthalein solution to each test tube.

25. Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the waste of a factory in their village was flowing into the pond, which probably caused the fish to die.

(a) Explain why the fish were dying.

(b) If the factory waste is acidic in nature, how can it be neutralised?

a) As Factory waste is disposed of in the river, it can kill the fish as factory waste may contain acids, bases and other toxic compounds.

b) If the factory waste is acidic in nature, it can be neutralised by adding basic substances.

26. Explain two neutralisation reactions related to a daily life situation.

Acidity is caused in the stomach as indigestion releases a lot of acids. This can be controlled by taking antacids like milk of magnesia.

(b) Ant’s sting

Ant’s sting releases formic acid into the skin. It can be neutralised by rubbing baking soda or putting in calamine lotion.

For chapter-wise NCERT Solutions , notes, textbooks, previous years’ question papers, and NCERT exemplar solutions of all the classes and subjects, visit BYJU’S website or download BYJU’S – The Learning App for a comprehensive learning experience.

Frequently Asked Questions NCERT Exemplar for Class 7 Science Chapter 5 Acids, Bases and Salts

Paheli is suffering from indigestion due to acidity. is it advisable to give her orange juice in this situation, and why.

No, orange juice is not advised because it is acidic in nature.

While playing in a park, a child was stung by a wasp. Some elders suggested applying a paste of baking soda and other lemon juice as the remedy. Which remedy do you think is appropriate and why?

Wasp releases a liquid substance into the body when it stings. This liquid will be acidic in nature hence baking soda should be applied as a remedy, but adding lemon juice will increase the pain and redness.

Form a sentence using the following words – baking soda, ant bite, moist, effect, neutralised, rubbing.

Explain two neutralisation reactions related to a daily life situation..

(b) Ant’s sting

Ant’s sting releases formic acid into the skin. It can be neutralised by rubbing baking soda or putting in calamine lotion.

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GK Questions on Acid Bases and Salts Class 7

Understanding the basics of acids, bases, and salts is essential for students, particularly in Class 7, as it forms the foundation of chemistry. These substances play a crucial role in everyday life, from the sour taste of lemon juice to the bitter taste of baking soda.

Our collection of 50 General Knowledge questions on acids, bases, and salts Class 7 for students aims to enhance their understanding and curiosity about these chemical compounds. Each GK questions is designed to be concise, with one-word answers, making it easier for students to grasp and retain key concepts. Dive in to test your knowledge and learn more about the fascinating world of chemistry

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50 GK Questions and Answer on Acid Bases and Salts Class 7

Q. What is the taste of acids?

Answer: Sour

Q. What is the taste of bases?

Answer: Bitter

Q. What color does litmus paper turn in acids?

Answer: Red

Q. What color does litmus paper turn in bases?

Answer: Blue

Q. What is the pH range of acids?

Answer: 0-7

Q. What is the pH range of bases?

Answer: 7-14

Q. What is the pH of a neutral solution?

Q. What gas is produced when acids react with metals?

Answer: Hydrogen

Q. What type of substance is NaOH ?

Answer: Base

Q. What type of substance is HCl?

Answer: Acid

Q. What substance is commonly used to neutralize stomach acid?

Answer: Antacid

Also Check: GK Question on Science

Q. What ion do acids release in water?

Q. What ion do bases release in water?

Answer: Hydroxide

Q. What is the common name for sodium chloride?

Answer: Salt

Q. What color does phenolphthalein turn in a base?

Answer: Pink

Q. What color does phenolphthalein remain in an acid?

Answer: Colorless

Q. What is the chemical formula for water?

Answer: H2O

Q. What is the common use of acetic acid?

Answer: Vinegar

Q. What type of reaction occurs when an acid and base react?

Answer: Neutralization

Q. What is produced in a neutralization reaction besides water?

Q. What is the chemical formula for sulfuric acid ?

Answer: H2SO4

Q. What is the chemical formula for calcium hydroxide ?

Answer: Ca(OH)2

Q. What is the common name for calcium carbonate ?

Answer: Chalk

Q. What is the effect of acids on blue litmus paper?

Q. What is the effect of bases on red litmus paper?

Q. What substance is used to test for carbon dioxide?

Answer: Limewater

Q. What gas is released when acids react with carbonates?

Answer: Carbon dioxide

Q. What is the main component of gastric acid?

Answer: HCl

Q. What is the chemical name for baking soda?

Answer: Sodium bicarbonate

Q. What is the common use of magnesium hydroxide ?

Q. What is the chemical formula for hydrochloric acid ?

Q. What is the common name for sodium hydroxide ?

Answer: Lye

Q. What is the effect of acidic soil on plants ?

Answer: Harmful

Q. What type of acid is found in citrus fruits ?

Answer: Citric

Q. What substance is used to clean swimming pools?

Answer: Chlorine

Q. What is the taste of baking soda?

Q. What color does turmeric turn in a base?

Q. What acid is used in car batteries?

Answer: Sulfuric

Q. What base is used in soap making?

Answer: Sodium hydroxide

Q. What is the effect of bases on turmeric paper?

Q. What type of acid is found in vinegar?

Answer: Acetic

Q. What gas is produced when acids react with bicarbonates ?

Q. What is the common name for H2SO4?

Answer: Sulfuric acid

Q. What is a common use for citric acid ?

Answer: Preservative

Q. What is the pH of pure water?

Q. What is the chemical formula for sodium chloride ?

Answer: NaCl

Q. What type of substance is KOH ?

Q. What ion is common in all acids?

Q. What ion is common in all bases?

Q. What is the effect of acidic solutions on methyl orange?

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Chapter 5: Acids, Bases and Salts

  Science

  (www.olympiadsuccess.com)

  Chapter 5: Acids, Bases and Salts

  Class: VII

  Multiple Choice Questions

The correct way of making a solution of acid in water is to

(a) add water to acid.

(b) add acid to water.

(c) mix acid and water simultaneously.

(d) add water to acid in a shallow container.

Products of a neutralisation reaction are always

(a) an acid and a base.

(b) an acid and a salt.

(c) a salt and water.

(d) a salt and a base.

Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed

(a) Yellow in both acid and base.

(b) Yellow in acid and red in base.

(c) Pink in acid and yellow in base.

(d) Red in acid and blue in base.

Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are

(a) red and blue.

(b) blue and red.

(c) pink and colourless.

(d) colourless and pink

When the soil is too basic, plants do not grow well in it. To improve its quality what must be added to the soil?

(a) Organic matter

(b) Quick lime

(c) Slaked lime

(d) Calamine solution

‘Litmus’, a natural dye is an extract of which of the following?

(a) China rose (Gudhal)

(b) Beetroot

(d) Blue berries (Jamun)

Neutralisation reaction is a

(a) physical and reversible change.

(b) physical change that cannot be reversed.

(c) chemical and reversible change.

(d) chemical change that cannot be reversed.

A solution changes the colour of turmeric indicator from yellow to red. The solution is

(c) neutral

(d) either neutral or acidic

Which of the following set of substances contain acids?

(a) Grapes, lime water

(b) Vinegar, soap

(c) Curd, milk of magnesia

(d) Curd, vinegar

Question 10

On adding phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution?

(b) Either acidic or basic

(c) Either acidic or neutral

(d) Either basic or neutral

Question 11

Which of the following is an acid-base indicator?

(a) Vinegar

(b) Lime water

(c) Turmeric

(d) Baking soda

Very Short Answer Questions

Question 12

Look at the given reaction.

Hydrochloric acid + Sodium hydroxide (base) → Sodium

chloride (salt) + Water

Sodium chloride formed in this reaction remains in solution form. Can we get solid sodium chloride from this solution?

Suggest a method (if any).

Hint: Evaporation

Question 13

State whether the following statements are true or false. Correct the false statements.

(a) All substances are either acidic or basic.

(b) A compound if acidic will turn all indicators red.

(c) Lime water turns red litmus blue.

(d) Common salt dissolved in water turns blue litmus red.

(e) Phenolphthalein is a natural indicator.

(f) Calamine can be used to treat ant’s sting.

(g) Lemon water is basic in nature.

(a) False. Substances can be neutral as well.

(b) False. Acids do not turn all indicators red.

(d) False. It does not change the colour of litmus at all.

(e) False. It is a man-made indicator.

(g) False. It is acidic in nature.

Question 14

Paheli is suffering from indigestion due to acidity. Is it advisable to give her orange juice in this situation and why?

No, because orange juice is acidic in nature.

Short Answer Questions

Question 15

Look at Figure 5.1 which shows solutions taken in test tubes A,B,C and D. What colour is expected when a piece of red litmus paper is dropped in each test tube? Nature of the solutions is given in the table for your help.

Question 16

While playing in a park, a child was stung by a wasp. Some elders suggested applying paste of baking soda and others lemon juice as remedy. Which remedy do you think is appropriate and why?

Wasp sting inject a liquid in the skin which is acidic in nature.

Hence, baking soda is the appropriate remedy, as it is basic in

nature and neutralises the acid.

Question 17

Form a sentence using the following words – baking soda, ant bite, moist, effect, neutralised, rubbing.

The effect of an ant bite can be neutralised by rubbing moist

baking soda.

Question 18

Match the substances in Column I with those in Column II.

(a) (iii); (b) (v); (c) (iv); (d) (i); (e) (ii)

Question 19

Fill the blanks in the following sentences

(a) Lemon juice and vinegar taste ___________ because they contain ___________.

(b) Turmeric and litmus are _________ acid-base indicators.

(c) Phenolphthalein gives _________ colour with lime water.

(d) When an acidic solution is mixed with a basic solution, they _________ each other forming _________ and water.

(a) Tartaric acid (i) soap

(b) Calcium hydroxide (ii) curd

(c) Formic acid (iii) unripe mangoes

(d) Sodium hydroxide (iv) ant's sting

(e) Lactic acid (v) lime water

Column I Column II

. (a) sour, acids (b) natural (c) pink (d) neutralise, salt

Long Answer Questions

Question 20

Boojho, Paheli and their friend Golu were provided with a test tube each containing China rose solution which was pink in colour. Boojho added two drops of solution ‘A’ in his test tube and got dark pink colour. Paheli added 2 drops of solution ‘B’ to her test tube and got green colour. Golu added 2 drops of solution ‘C’ but could not get any change in colour. Suggest the possible cause for the variation in their results.

‘A’ is an acidic solution.

‘B’ is a basic solution.

‘C’ is a neutral solution.

Question 21

Fill in the cross word given as Figure 5.2 with the help of the clues provided.

(2) The solution which does not change the colour of either red or blue litmus.

(4) Phenolphthalein gives pink colour in this type of solution.

(7) Colour of blue litmus in lemon juice.

(1) It is used to test whether a substance is acidic or basic.

(3) It is a natural indicator and gives pink colour in basic solution.

(5) Nature of ant’s sting.

(6) It is responsible for increase in temperature during a

neutralisation reaction.

Question 22

A farmer was unhappy because of his low crop yield. He discussed the problem with an agricultural scientist and realised that the soil of his field was either too acidic or too basic. What remedy would you suggest the farmer to neutralise the soil?

Hint: If the soil is too acidic, it is treated with bases such as

quick lime (calcium oxide) or slaked lime (calcium hydroxide).

If the soil is too basic, organic matter is added to it. Organic

matter releases acids which neutralises the basic nature of the

Question 23

You are provided with four test tubes containing sugar solution, baking soda solution, tamarind solution, salt solution. Write down an activity to find the nature (acidic/basic/neutral) of each solution.

. Hint: Use both red and blue litmus solutions and predict the

colours in each case.

Question 24

You are provided with three test tubes A, B and C as shown in Figure 5.3 with different liquids. What will you observe when you put

(a) a piece of blue litmus paper in each test tube.

(b) a piece of red litmus paper in each test tube.

(c) a few drops of phenolphthalein solution to each test tube.

Question 25

Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the waste of a factory in their village is flowing into the pond which probably caused the fish to die.

(a) Explain why the fish were dying.

(b) If the factory waste is acidic in nature, how can it be

neutralised?

(a) Since factory waste may contain acids or bases, it can

kill the fish.

(b) If the factory waste is acidic in nature, it can be

neutralised by adding basic substances.

Question 26

Explain two neutralisation reactions related to daily life situation.

• Indigestion

Other Chapters

• Chapter 1: Nutrition in Plants
• Chapter 2: Nutrition in Animals
• Chapter 3: Fibre to Fabric
• Chapter 4: Heat
• Chapter 6: Physical and Chemical Changes
• Chapter 7: Weather, Climate and Adaptations of Animals to Climate
• Chapter 8: Winds, Storms and Cyclones
• Chapter 9: Soil
• Chapter 10: Respiration in Organisms
• Chapter 11: Respiration in Animals and Plants
• Chapter 12: Reproduction in Plants
• Chapter 13: Motion and time
• Chapter 14: Electric Current and its Effects
• Chapter 15: Light
• Chapter 16: Water - A Precious Resource

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