Question

What would you observe when :

(a) blue litmus is introduced into a solution of hydrogen chloride gas,

(b) red litmus paper is introduced into a solution of ammonia in water,

(c) red litmus paper is introduced in caustic soda solution ?

Answer 1

(a) HCl is acidic in nature. When the Hydrogen chloride solution is added to the blue litmus. Then, blue litmus will turns into red showing the acidic nature of the hydrogen chloride gas.
(b) Ammonia is basic in nature and bases turn red litmus into blue. Hence, red litmus paper turns blue when introduced into a solution of ammonia in water.

(c) Caustic soda salt $\left(NaOH\right)$ is alkaline in nature, therefore it turns red litmus into blue .