Aqueous solution of which of the following salts can turn red litmus blue?Only one correct answerA.Aluminium chlorideB.Potassium nitrateC.Sodium acetateD.Sodium sulphate

The answer is C. Sodium acetate.

Here's why:

Aqueous solutions that can turn red litmus paper blue are basic (alkaline) in nature.

A. Aluminium chloride forms an acidic solution in water, so it would turn blue litmus paper red, not red litmus paper blue.

B. Potassium nitrate is a neutral salt and does not affect the color of litmus paper.

D. Sodium sulphate is also a neutral salt and does not affect the color of litmus paper.

C. Sodium acetate, however, is a basic salt. When it dissolves in water, it undergoes hydrolysis to form a weak base (acetate ions) and a strong base (sodium hydroxide). The solution is therefore basic and can turn red litmus paper blue.