An aqueous solution of copper sulphate is acidic in nature because the salt undergoes

An aqueous CuSO4 solution is acidic because the Cu2+ cation undergoes hydrolysis: the metal ion forms a hydrated complex that can donate protons to water, producing H3O+ and thereby lowering pH. Specifically, Cu2+ ions interact with water to give species such as [Cu(H2O)6]2+ which release H+ (or equilibrate to CuOH+ + H+), producing an acidic solution . This follows the general principle that salts formed from a weak base and a strong acid give acidic solutions due to cation hydrolysis; detecting an acidic reaction indicates hydrolysis of the salt in water [1]. Electrolysis, dialysis or photolysis are not the causes of the intrinsic acidity of the dissolved salt.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Activity 2.14 > p. 29