Question

Cu\(^+\) is unstable in solution and undergoes simultaneous oxidation and reduction according to the reaction \(2\text{Cu}^+(\text{aq}) \rightarrow \text{Cu}^{2+}(\text{aq}) + \text{Cu(s)}\). Choose the correct \(E^\circ\) for the above reaction if \(E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.34\,\text{V}\) and \(E^\circ_{\text{Cu}^+/\text{Cu}} = +0.15\,\text{V}\).

• A. \(-0.38\,\text{V}\)
• B. \(+0.49\,\text{V}\)
• C. \(+0.38\,\text{V}\)
• D. \(-0.19\,\text{V}\)

Hint:

Disproportionation reactions often have positive cell potentials.

Answer 1

The Correct Option is C

Step 1: Disproportionation reaction: \[ E^\circ = E^\circ_{\text{red}} - E^\circ_{\text{ox}} \]
Step 2: \[ E^\circ = 0.34 - (-0.04) = 0.38\,\text{V} \]