Write redox couples involved in the reaction (i) to (iv) given below in the question
(i) `Cu + Zn^(2+) to Cu^(2+) + Zn`
(ii)`Mg +Fe^(2+) to Mg^(2+) + Fe`
(iii)`Br_2 + 2 Cl^(-) to Cl_2 + 2 Br^-`
(iv)` Fe + Cd^(2+) to Cd + Fe^(2+)`

Explanation

To write the redox couples involved in the reactions (i) to (iv), we need to identify the species that are oxidized and reduced in each reaction. A redox couple consists of the oxidized form and the reduced form of a substance, typically written in the format: oxidized species / reduced species.

### Step-by-Step Solution

**(i)** Reaction: `Cu + Zn^(2+) → Cu^(2+) + Zn`

1. **Identify Oxidation and Reduction:**
- Copper (Cu) is oxidized as it goes from 0 to +2 (Cu → Cu²⁺).
...