Mention the reactions occurring at (i) anode, (ii) cathode, during working of a mercury cell. Why does the voltage of a mercury cell remain constant during its operation?

Explanation

To answer the question regarding the reactions occurring at the anode and cathode during the operation of a mercury cell, as well as the reason why the voltage remains constant, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Identify the Components of the Mercury Cell:**
- The mercury cell consists of zinc (Zn) as the anode, mercury oxide (HgO) as the cathode, and potassium hydroxide (KOH) as the electrolyte.

2. **Reactions at the Anode:**
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