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NCERT solutions Science Class 7 chapter 5 Acids, Bases and Salts

Chapters

NCERT Science Class 7

Science Textbook for Class  7

Chapter 5 - Acids, Bases and Salts

Pages 56 - 57

State the differences between acids and bases.

Q 1 | Page 56

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

Q 2 | Page 56

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

Q 3 | Page 56

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

Q 4 | Page 56

Describe the process of neutralization with the help of an example.

Q 5 | Page 56

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

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

Q 6.1 | Page 56

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

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

Q 6.2 | Page 56

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

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

Q 6.3 | Page 56

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

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

Q 6.4 | Page 56

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

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

Q 6.5 | Page 56

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?

Q 7 | Page 56

Explain why An antacid tablet is taken when you suffer from acidity.

Q 8.1 | Page 56

Explain why Calamine solution is applied on the skin when an ant bites.

Q 8.2 | Page 56

Explain why:Factory waste is neutralised before disposing it into the water bodies.

Q 8.3 | Page 56

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? You have only turmeric indicator.

Q 9 | Page 57

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

Q 10 | Page 57

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?

1) All four

2) a and d

3) b and c

4) only d

Q 11 | Page 57

NCERT Science Class 7

Science Textbook for Class  7
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