What is the equation for the reaction which takes place at the cathode ?

Explanation

To determine the equation for the reaction that takes place at the cathode during electrolysis, we need to understand the process involved:

1. **Identify the Type of Reaction**: At the cathode, a reduction reaction occurs. This means that a substance gains electrons.

2. **General Representation of Reduction**: The general equation for a reduction reaction can be represented as:
\[ M^{n+} + n e^- \rightarrow M \]
...