Write redox couples involved in the reactions (a) to (d) given in quesiton 34.

Explanation

To solve the problem of identifying the redox couples involved in the reactions (a) to (d), we will analyze each reaction step by step, focusing on the oxidation and reduction processes.

### Step-by-Step Solution

**Reaction (a):**
\[ \text{Cu} + \text{Zn}^{2+} \rightarrow \text{Cu}^{2+} + \text{Zn} \]

1. **Identify Oxidation and Reduction:**
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