In Castner `-` Kellner cell for the manufacture of `NaOH(` caustic soda `), Hg` acts as cathode as well as anode. True/False

Explanation

To determine whether the statement "In Castner-Kellner cell for the manufacture of NaOH, Hg acts as cathode as well as anode" is true or false, let's analyze the functioning of the Castner-Kellner cell step by step.

### Step-by-Step Solution:

1. **Understanding the Castner-Kellner Cell**:
- The Castner-Kellner cell is an electrolytic cell used for the production of sodium hydroxide (NaOH) from brine (sodium chloride solution).

2. **Components of the Cell**:
- The cell consists of two compartments: the left compartment and the right compartment.
- The left compartment contains a mercury cathode, while the right compartment has an iron anode.

3. **Role of Mercury**:
- In the left compartment, mercury acts as the cathode. Here, it facilitates the reduction of sodium ions (Na⁺) from the brine solution.
- In the right compartment, mercury acts as the anode. It participates in the oxidation reactions.

4. **Electrode Functionality**:
- At the cathode (left compartment), the reduction reaction occurs, where sodium ions gain electrons and form sodium metal, which amalgamates with mercury.
- At the anode (right compartment), oxidation occurs, where the mercury releases electrons.

5. **Conclusion**:
- Since mercury serves as both the cathode in one compartment and the anode in another, the statement is **True**.

### Final Answer:
The statement is **True**.