NCERT Solutions for Class 7 Science Chapter 5 Acid Base and Salt
Learn from School Connect Online in this chapter we will learn about Acids, bases and salts which are the three important groups of chemical substances that are used by us in different ways. Some of the acids, bases and salts occur in nature and they can be made artificially in factories also.NCERT Solutions for Class 7 Science Chapter 5 Acid Base and Salt
Download PDF of NCERT Solutions for Class 7 Science
NCERT Solutions Download Class 7 | Chapter Name | NCERT Solutions Download Class 7 | Chapter Name |
NCERT Solutions For Class 7 Science Chapter 1: Nutrition In Plants | Nutrition in Plants | NCERT Solutions for Class 7 Chapter 10 Respiration in Organisms | Respiration in Organisms |
NCERT Solutions for Class 7 Chapter 2 Nutrition in Animals | Nutrition in Animals | NCERT Solutions for Class 7 Chapter 11 Transportation in Animals and Plants | Transportation in Animals and Plants |
NCERT Solutions for Class 7 Chapter 3 Fibre to Fabric | Fibre to Fabric | NCERT Solutions for Class 7 Chapter 12 Transportation in Animals and Plants | Reproduction in Plants |
NCERT Solutions for Class 7 Chapter 4 Heat | Heat | NCERT Solutions for Class 7 Chapter 13 Motion and Times | Motion and Times |
NCERT Solutions for Class 7 Chapter 5 Acids,Bases and Salts | Acids,Bases and Salts | NCERT Solutions for Class 7 Chapter 14 Electric Current and its Effects | Electric Current and its Effects |
NCERT Solutions for Class 7 Chapter 6 Physical and Chemical Changes | Physical and Chemical Changes | NCERT Solutions for Class 7 Chapter 15 Light | Light |
NCERT Solutions for Class 7 Chapter 7 | Weather,Climate and Adaptations of Animals to Climate | NCERT Solutions for Class 7 Chapter 16 Water;A precious resource | Water;A precious resource |
NCERT Solutions for Class 7 Chapter 8 | Winds Storms and Cyclones | NCERT Solutions for Class 7 Chapter 17 Forests;Our life line | Forests;Our life line |
NCERT Solutions for Class 7 Chapter 9 | Soil | NCERT Solutions for Class 7 Chapter 18 Waste water story | Waste water story |
NCERT Solutions for Class 7 Science Chapter 5 Acid Base and Salt
Exercise Questions
1. State differences between acids and bases.
Solution:
Acids | Bases |
Acids are sour in taste | Bases are bitter in taste |
Acids turn blue litmus paper into red color | The base does not change the colour of blue litmus paper |
Acids does not change the colour of the red litmus | Bases turn red litmus paper to blue color |
Acids do not change the colour of turmeric | Bases turn turmeric to red |
2. Ammonia is found in many household products, such as window cleaners. It turns red litmus blue. What is its nature?
Solution:
The answer is basic in nature
3. Name the source from which litmus solution is obtained. What is the use of this solution?
Solution:
Litmus solution is extracted from lichens. Litmus solution is used as an indicator to find acidic and basic nature of a solution.
4. Is the distilled water acidic/basic/neutral? How would you verify it?
Solution:
Distilled water is neutral in nature, and this can be tested by using red and blue litmus paper. In either of the cases, colour remains unchanged.
5. Describe the process of neutralisation with the help of an example.
Solution:
Neutralisation is a reaction between an acid and a base. Here both acids and bases get neutralised For example, when sodium hydroxide (NaOH) is added to hydrochloric acid (HCl), sodium chloride (NaCl) and water (H2O) are obtained.
NaOH + HCl → NaCl + H2O + Heat
6. Mark ‘T’ if the statement is true and ‘F’ if it is false:
(i) Nitric acid turn red litmus blue. (T/F)
Sol : False
(ii) Sodium hydroxide turns blue litmus red. (T/F)
Sol : False
(iii) Sodium hydroxide and hydrochloric acid neutralise each other and form salt and water. (T/F)
Sol : True
(iv) Indicator is a substance which shows different colours in acidic and basic solutions. (T/F)
Sol : True
(v) Tooth decay is caused by the presence of a base. (T/F)
Sol : False
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?
Solution:
Dorji can taste a few drops out of soft drinks bottles, acidic solution is sour in taste, basic solution is bitter in taste, and the neutral solution has no taste. Along with tasting, Dorji can use litmus paper to test the nature of soft drinks. He should use blue litmus paper to test the acidic solution. Dorji has to put a drop of solution on blue litmus. If it turns red then the solution will be acidic in nature.
Similarly, he can use red litmus paper to test the basic solution. He has to put a drop of solution on red litmus. If it turns blue then the solution will be basic in nature.
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.
Solution:
- The antacid tablet contains a base like milk of magnesia which neutralises the acid produced in the stomach. Hence, it is used while suffering from acidity.
- When an 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.
- Factory wastes are acidic in nature which may cause harm to aquatic life. Hence, they are neutralised by using a base before disposing it into the water bodies.
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.
Solution:
Add solution to a container with a turmeric indicator. If the solution is NaOH, it would turn the turmeric indicator to red. To the same container, add test solution number 2. If the added solution is sugar, the solution indicator remains unchanged because mixture of a basic and neutral solution will remain basic in nature.
Similarly, add the test solution number 3 to another container with a turmeric indicator. If the indicator changes yellow to blue then the solution will be hydrochloric acid.
10. Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.
Solution:
Above solution may be neutral or basic in nature as both of them will not change the colour of the blue litmus paper.
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, c and d
(iv) only d
Solution:
Only d) is correct
CBSE Notes for Class 7 Science Free Download for All Chapters
CBSE Class 7 Science Study Notes | CBSE Class 7 Science Study Notes |
Nutrition in Plants Class 7 Notes Chapter 1 | Respiration in Organisms Class 7 Notes Chapter 10 |
Nutrition in Animals Class 7 Notes Chapter 2 | Transportation in Animals and Plants Class 7 Notes Chapter 11 |
Fibre to Fabric Class 7 Notes Chapter 3 | Reproduction in Plants Class 7 Notes Chapter 12 |
Heat Class 7 Notes Chapter 4 | Motion and Times Class 7 Notes Chapter 13 |
Acids,Bases and Salts Class 7 Notes Chapter 5 | Electric Current and its Effects Class 7 Notes Chapter 14 |
Physical and Chemical Changes Class 7 Notes Chapter 6 | Light Class 7 Notes Chapter 15 |
Weather,Climate and Adaptations of Animals to Climate Class 7 Notes Chapter 7 | Water;A precious resource Class 7 Notes Chapter 16 |
Winds Storms and Cyclones Class 7 Notes Chapter 8 | Forests;Our life line Class 7 Notes Chapter 17 |
Soil Class 7 Notes Chapter 9 | Waste water story Class 7 Notes Chapter 18 |
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