Statement-1: Many copper (I) compounds are unstable in aqueous
solution and undergo disproportionation
Statement-2: ${\mathrm{Cu}}^{2+}$ is more stable than ${\mathrm{Cu}}^{+}$ because of much more negative ${\mathrm{\Delta }}_{hyd}{\mathrm{H}}^{\circ }$ of ${\mathrm{Cu}}^{2+}$ than ${\mathrm{Cu}}^{+}$, which more than compensates for second ionisation enthalpy.

In an aqueous solution, many copper compounds become unstable and undergo a disproportionation reaction.
Cuprous ion (Cu+) is unstable in an aqueous medium because the stability of the aqueous medium depends on the energy of hydration.
In an aqueous solution, Cu+ is oxidised to produce stable form of Cu2+.

$2{\mathrm{Cu}}^{+}\to \mathrm{Cu}+{\mathrm{Cu}}^{2+}$.