Question

All Cu(II) halides are known, except ithe iodide, the reason for it is that

• A. Cu⁺² has much more negative hydration enthalpy.
• B. Iodide is bulky ion.
• C. Cu⁺² ion has smaller size.
• D. Cu⁺² oxidises Iodide toiodine.

Answer 1

The Correct Option is D

Copper (II) ion \(\text{(Cu}^{2+}\text{)}\) has a high oxidizing ability. In the presence of iodide ion (I^-), \(\text{(Cu}^{2+}\text{)}\) readily oxidizes iodide to form iodine \((\text{I}_2)\). The reaction can be represented as follows:
\(2\text{Cu}^{2+} + 4\text{I}^- \rightarrow 2\text{Cu}^+ + \text{I}_2\)
As a result of this oxidation reaction, \(\text{(Cu}^{2+}\text{)}\) is reduced to \(\text{(Cu}^{1+}\text{)}\), and iodide is oxidized to iodine.
This chemical behavior prevents the stable formation of \(\text{Cu(II)}\) iodide \(\text{(CuI}_2\text{)}\) because the \(\text{(Cu}^{2+}\text{)}\)ion oxidizes the iodide ions to form iodine. Instead, copper (I) iodide\( (CuI)\) is formed, where the \(\text{(Cu}^{1+}\text{)}\) ion is stabilized by the iodide ions.
Therefore, the correct reason why \(\text{Cu(II)}\) iodide is not known is option (D) \(\text{(Cu}^{2+}\text{)}\) oxidizes iodide to iodine.