Question

The aqueous solution of one of the following salts will turn red litmus to blue. This salt is
(a) potassium sulphate
(b) sodium sulphate
(c) sodium chloride
(d) potassium carbonate

Answer 1

Answer:

Explanation:

The rg8ht answer is option D

Answer 2

Among the given reagents,  an aqueous solution of potassium carbonate can turn Red litmus to blue.

• A base or an alkali turns red litmus to blue.
• All the given reagents are salts. They will dissociate to form respective acids and bases when dissolved in water.
• Potassium sulfate on dissociation produces Potassium hydroxide and sulphuric acid, which are strong base and acid respectively. So the resulting solution must be neutral.
• Sodium sulfate on dissociation produces Sodium hydroxide and sulphuric acid, that is, a strong base and acid respectively. So the resulting solution must be neutral.
• Similarly, Sodium chloride on dissociation produces Sodium hydroxide and hydrochloric acid, that is, a strong base and acid respectively. So the resulting solution must be neutral.
• In the case of Potassium carbonate, the acid, and base produced on dissociation are carbonic acid and potassium hydroxide respectively. Carbonic acid is a weak acid while potassium hydroxide is a strong base.
• Hence, the resultant solution is basic and turns red litmus blue.