Question

Identify the reaction from following so that the standard potential of \(\text{Cu}^{+2}/\text{Cu}\) electrode is 0.34 V. with respective to SHE ?

• A. \(\text{Cu}\rightarrow \text{Cu}^{+2}+2e^-\)
• B. \(\text{Cu}^{+2}+2e^-\rightarrow \text{Cu}\)
• C. \(\text{Cu}^+\rightarrow \text{Cu}^{+2}+e^-\)
• D. \(\text{Cu}^{+3}\rightarrow \text{Cu}^{+2}+e^-\)

Hint:

Standard electrode potentials are written for reduction half reactions.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
By IUPAC convention, a standard electrode potential refers to the reduction half reaction measured against the standard hydrogen electrode (SHE).

Step 2: Detailed Explanation:
For the \(\text{Cu}^{2+}/\text{Cu}\) electrode, the reduction is
\[ \text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}, \quad E^\circ = +0.34\ \text{V} \]
Option (A) is the reverse (oxidation), so its potential would be \(-0.34\) V. Options (C) and (D) involve \(\text{Cu}^+\) and \(\text{Cu}^{3+}\), which are not the \(\text{Cu}^{2+}/\text{Cu}\) couple, and are oxidations.

Step 3: Final Answer:
Option (B) is the reaction for \(E^\circ = 0.34\) V.

Final Answer:
Standard potentials are for reduction half reactions. \[ \boxed{\text{(B) }\text{Cu}^{2+}+2e^-\rightarrow\text{Cu}} \]