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 neutralize each other and form salt and water. (T/F)

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

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

i. False.

Nitric acid is acidic in nature. Thus, it turns blue litmus to red.

ii. False.

The substances that turn red litmus to blue are basic in nature. Sodium hydroxide also turns red litmus to blue. Thus, it is basic in nature.

iii. True.

When sodium hydroxide (NaOH) is added to hydrochloric acid (HCl), sodium chloride (NaCl) and water are obtained. It is an example of neutralization reaction.

iv. True.

Special type of substances are used to test whether a substance is acidic or basic. These substances are known as indicators.

v. False.

Tooth decay is caused by the presence of a acid.