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

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Last updated date: 25th Jul 2024
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Solutions for NCERT, Class 7 Science, Chapter 5, Acids, Bases and Salts, are Now Available for a Free Download at Vedantu

Free PDF download of NCERT Exemplar for Class 7 Science Chapter - 5 Acids, Bases and Salts solved by expert Science teachers on Vedantu.com as per NCERT (CBSE) Book guidelines. All Chapter - 5 Acids, Bases and Salts exercise questions with solutions to help you to revise the complete syllabus and score more marks in your examinations.

Every NCERT Solution is provided to make the study simple and interesting on Vedantu. Subjects like Science, Maths, English will become easy to study if you have access to NCERT Solution for Class 7 Science, Maths solutions and solutions of other subjects. You can also download NCERT Solutions for Class 7 Maths to help you to revise the complete syllabus and score more marks in your examinations.

Science is an important subject for the students of Class 7. Many chapters that are covered in the NCERT textbook of Class 7, deals with the fundamentals of Science, and Chapter 5 which is, Acids, Bases and Salts is one of them.

To master this chapter, the students have to practice a lot, or as often and as much as possible. But only practising the solutions cannot help alone, because students have to make sure that the solutions they have done are the right ones. And therefore, Vedantu brings to the students of Class 7, the complete solutions for Chapter 5, of the Science subject. Which is Acid, Bases and Salts.

Access NCERT Exemplar Solutions for Class 7 Science(Chemistry) Chapter 5 - Acids, Bases and Salts (Examples, Easy Methods and Step by Step Solutions)

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

Ans: The correct answer is option (b). When we add water to acid, it releases some energy. We can feel this energy by touching the surface of the test tube. Sometimes, released heat is too huge. Because of this glasses of test tube may prove wrong and acid can split over. So, in practice, you have to take an excessive amount of water and mix acid drop by drop. In order that heat generated can be cooled down by this water and mistakes can be prevented.


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

Ans: The correct answer is option (c). Bases and acids cancel each other’s qualities and properties. They make water and salt as products.


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

Ans: The correct answer is option (b), Yellow in acid and red in 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

Ans: The correct answer is option (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

Ans: The correct answer is option (a). To improve its quality organic matter must be added to the soil.


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

(a) China rose (Gudhal) 

(b) Beetroot 

(c) Lichen 

(d) Blueberries (Jamun)

Ans: The correct answer is option (c).


7. 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

Ans: The correct answer is option (d). A chemical reaction where base and acid reacts with each other quantitatively, known as a neutralization reaction. It is a permanent process.


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

(a) basic 

(b) acidic 

(c) neutral 

(d) either neutral or acidic

Ans: The correct answer is option (a).


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

Ans: The correct answer is option (d). Curd contains ‘lactic acid’ and vinegar contains ‘acetic acid’.


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

(a) Basic 

(b) Either acidic or basic 

(c) Either acidic or neutral 

(d) Either basic or neutral

Ans: The correct answer is option (c). With acidic/ neutral solutions, the colour of the phenolphthalein indicator will not change.


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

(a) Vinegar 

(b) Lime water 

(c) Turmeric 

(d) Baking soda

Ans: The correct answer is option (c). In acidic solution colour of turmeric is yellow but in a basic solution, it gives red colour.


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).

Ans: In water ‘sodium chloride’ is soluble and it gives a solution of common salt. By ‘evaporation procedure’ we can get ‘solid sodium chloride’.


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

(a) All substances are either acidic or basic.

Ans: The given statement is false. In nature, all substances can be ‘acidic’, ‘basic’ or ‘neutral’. 

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

Ans: The given statement is false. Acids do not turn all indicators red.

(c) Lime water turns red litmus blue. 

Ans: The given statement is true. 

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

Ans: The given statement is false. The colour of litmus paper will not change. 

(e) Phenolphthalein is a natural indicator. 

Ans: The given statement is false. A man-made indicator is Phenolphthalein. 

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

Ans: The given statement is true. 

(g) Lemon water is basic in nature.

Ans: The given statement is false. The nature of ‘Lemon water’ is acidic.


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

Ans: Orange juice is acidic. So, it is not advisable to take orange juice in her situation.


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? Nature of the solutions is given in the table for your help.

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Test

Nature of Solutions

Change in colour of Red litmus

A

Neutral


B

Basic


C

Acidic


D

Neutral


Ans: According to the given condition:

Test

Nature of Solutions

Change in colour of Red litmus

A

Neutral

Zero change

B

Basic

Colour will change into blue

C

Acidic

Zero change

D

Neutral

Zero change


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

Ans: Bicarbonate of soda has a basic nature, whereas juice has an acidic tendency. Because wasp stings emit methanoic acid into the string region, which causes irritation, applying baking soda paste is a better cure than applying lemon juice paste. Baking soda has a very basic nature.


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

Ans: The arranged form of given words: 

“The effect of ant bite can be neutralized by rubbing moist baking soda on the affected area”.


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

Column I

Column II

(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

Ans: The correct table is given below:


Column I

Column II

(a) Tartaric acid

(iii) Unripe mangoes

(b) Calcium hydroxide

(v) Lime water

(c) Formic acid

(iv) Ant’s sting

(d) Sodium hydroxide

(i) soap

(e) Lactic acid

(ii) Curd


19. Fill the blanks in the following sentences 

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

Ans: sour, acids

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

Ans: natural

(c) Phenolphthalein gives _________ colour with lime water. 

Ans: pink

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

Ans: neutralize, salt


Long Answer 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.

Ans: The 'China rose' is a natural indication that transforms the colour of acid to pink, the colour of base to green, and the colour of neutral solutions remains unchanged. As a result, solution A is acidic. The solution B serves as a foundation. Solution C is a non-reactive solution.


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

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Across 

(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. 

Down 

(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.

Ans: Across

(2) Neutral

(4) Base

(7) Red

Down

(1) Indicator

(3) Turmeric

(5) Acidic

(6) Heat


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?

Ans: When the soil in his field becomes too acidic, 'bases' such as slaked lime (calcium hydroxide)' or 'quicklime (calcium oxide)' are used to treat it. If his field's soil is too basic, organic matter is put to it. Organic matter produces acids, which neutralise the soil's natural (basic) character.


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.

Ans: We can determine the nature of each solution (acidic/basic/neutral) by tasting the solution in the test tube.

Sugar solution: The sugar solution will have a sweet flavour. It has neither a sour nor a bitter flavour. As a result, it is classified as a neutral solution.

Baking soda solution: The baking soda solution has a bitter taste. As a result, it falls within the category of a fundamental solution.

Tamarind solution: The tamarind solution will have a sour flavour. As a result, it falls under the acidic solution category.

Salt solution: The salt solution will have a salty flavour. It has neither a sour nor a bitter flavour. As a result, it is classified as a neutral solution.


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.

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Ans: You will observe:

Test tube

Effect on Blue litmus

Effect on Red litmus

Effect on Phenolphthalein

A

Changes in red

Remains red

Colourless

B

Remains blue

Changes in blue

Pink colour

C

Remains blue

Remains red

Colourless


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. 

Ans: Factory wastes may include a significant proportion of basic or acidic substances. These pollutants make it harder to live in the water.

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

Ans: The acids will be neutralised by the base. We can make water less dangerous and neutral by adding the base (limestone, lime, etc.) to it.


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

Ans: The following are two neutralisation reactions that occur in everyday situations:

a) Digestive disorders: Hyperacidity occurs when the stomach produces too much 'hydrochloric acid.' Digestive problems develop as a result of this. Basic ingredients such as milk of magnesia' or 'baking soda' can be used to treat the acid.

b) Ant-bite: The sting of an ant causes the body to produce 'methanoic acid' or 'formic acid.' These acids induce discomfort and a burning feeling. Because moist baking soda is basic in nature, rubbing it on the problem solves it.


Importance of the NCERT Exemplar solutions for the Class 7, Chapter 5, Acid, Bases and Salts.

The solutions for the Class 7 NCERT Exemplar, Chapter 5, Acid, Bases and Salts, help the students in the following manner.

  • In comparing their answers with the one provided in the solutions, and therefore making sure that they are on the right path.

  • Solutions provide the students with the best way to answer the questions.

Considering these points, Vedantu has brought the solutions for the Class 7 NCERT Exemplar, Science subject, Chapter 5, Acid, Bases and Salts, completely free of cost for all the students to download.


Also, if you are looking for the solutions to the other subjects of NCERT Class 7 you can find it here: NCERT Solutions for Class 7 (2024-25 Session) Maths, Science, SST, English and Hindi (vedantu.com).

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

1. How can I master Chapter 5 Acid, Bases and Salts, of the Class 7 Science NCERT Exemplar?

For mastering the fifth chapter of Class 7 NCERT Exemplar Science, which is Acid, Bases and Salts, students are required to have as much practice as possible. Because for solving the problems of the NCERT exemplar Science, students have to read the chapter many times in a search of finding a correct answer, and each time they read the chapter, the chapter gets revised. Therefore, towards the end of solving the NCERT exemplar Science problems, the students get the complete revision of Chapter 5 Acid, Bases and Salts.

2. How many questions are there in the NCERT Exemplar Class 7 Science Chapter 5: Acids, Bases and Salts?

There are a total of 26 questions given in the NCERT Exemplar Class 7 Science, Chapter 5 Acid, Bases and Salts, which are divided in the following manner:

  • 1 to 11 Multiple-choice type questions.

  • 12 to 14 Very short answer type questions.

  • 15 to 17 Short answer type questions.

  • 18 matching the column.

  • 19 Fill in the blanks, which are four in total.

  • 20 to 26 Long answer type questions.

In such a manner the NCERT Exemplar Class 7 questions are divided for Chapter 5 which is Acid, Bases and Salts.

3. Why do I need to solve the questions for the Exemplar Class 7 NCERT Science, Chapter 5 Acid, Base and Salts?

Because solving the questions for the chapter of Acids, Base and Salts, gives the students the very much required practice of the chapter. Also, simply understanding the topics of the chapter does not mean that you have mastered the chapter, students are required to put their understanding to the test, and the questions for the NCERT Exemplar Class 7 Science, Chapter 5 Acid, Base and Salts provides that type of practice to the students. Therefore, it becomes very much important for the students to solve the questions for this chapter.

4. Where can find the solutions for the Class 7 NCERT Science, Chapter 5 Acid, Bases and Salts?

First of all, if you have solved all the 26 questions of the Class 7 NCERT Science, Chapter 5 Acid, Bases and Salts, you have done a great job. Now, since you are looking for the solutions of the same, here is the good news for you, which is, you do not have to look further for the solutions for the NCERT exemplar Class 7 Science, Chapter 5 Acid, Bases and Salts because Vedantu has it all. Yes, at Vedantu you can easily find the complete solutions for Class 7 NCERT Science, Chapter 5 Acid, Bases and Salts.

5. What makes the solutions that Vedantu provides for the Class 7 NCERT Science Chapter 5 Acid, Bases and Salts a better option?

Vedantu aims at providing the best of the material to the students, and therefore all the material that Vedantu provides is prepared with the care of expert teachers who have years of experience. Also, the solutions that Vedantu provides for NCERT exemplar Class 7 Science, Chapter 5, Acid, Bases and salts come in a downloadable PDF Format which is available for free download to all the students. So that all the students of Class 7 have a benefit from it.