Explain why `Cu^+` ion is not stable in aqueous solution?

Explanation

In aqueous medium `Cu^(2+)` is more stable than `Cu^+`. This is because of much higher hydration enthalpy of `Cu^(2+)` compared to `Cu^+`. Therefore `Cu^+` compounds-are unstable in aqueous solution and undergoes disproportionation as shown below: `2Cu^+(aq)toCu^(2+)+(aq)+Cu(s)`