Science

Acids, Bases and Salts

Question:

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:

Name of the substances Effect on turmeric indicator
1. Hydrochloric acid Yellow to blue
2. Sodium hydroxide Yellow to red
3. Sugar solution No change

previuos
next

Acids, Bases and Salts

Q 1.

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

Q 2.

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)

Q 3.

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

Q 4.

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)
(id) 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)

Q 5.

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.

Q 6.

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

Q 7.

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

Q 8.

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

Q 9.

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 10.

State differences between acids and bases?

Q 11.

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.