Unit 8 The D And F Block Elements (Intext Questions-7)
Intext Question
8.9 Explain why $\mathrm{Cu}^{+}$ ion is not stable in aqueous solutions?
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Answer
In an aqueous medium, $\mathrm{Cu}^{2+}$ is more stable than $\mathrm{Cu}^{+}$. This is because although energy is required to remove one electron from $\mathrm{Cu}^{+}$to $\mathrm{Cu}^{2+}$, high hydration energy of $\mathrm{Cu2+}$ compensates for it. Therefore, $\mathrm{Cu}^{+}$ion in an aqueous solution is unstable. It disproportionates to give $\mathrm{Cu}^{2+}$ and $\mathrm{Cu}$.
$2 \mathrm{Cu _{(a q)}}^{+} \longrightarrow \mathrm{Cu}^{2+}{ _{(a q)}}+\mathrm{Cu _{(s)}}$