Question

The salt whose aqueous solution will turn blue litmus to red is ______.

Options

• ammonium sulphate

• sodium acetate

• sodium chloride

• potassium carbonate

Answer 1

The salt whose aqueous solution will turn blue litmus to red is ammonium sulphate.

Explanation:

Ammonium sulphate [(NH₄)₂SO₄] is formed from a weak base, ammonium hydroxide (NH₄OH), and a strong acid, sulphuric acid (H₂SO₄). On dissolving in water, (NH₄)₂SO₄ hydrolyses to form more H⁺ ions than OH⁻ ions. As the aqueous solution of the salt (NH₄)₂SO₄ is acidic, it turns blue litmus red.