Acids, Bases and Salts


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


The reaction between an acid and a base is known as neutralisation. Salt and water are produced in this process with the evolution of heat.
Antacids like milk of magnesia (magnesium hydroxide), baking soda, etc. which contain a base are used for reducing acidity in stomach when excessive acid released by glands.


Acids, Bases and Salts

Q 1.

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 2.

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 3.

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

Q 4.

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

Q 5.

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

Q 6.

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

Q 7.

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 8.

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 9.

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

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.