In Moissan's method the electrodes were

Options

A. Graphite
B. Pt
C. Ni
D. Pt-Ir-alloy

Explanation

To answer the question regarding the electrodes used in Moissan's method, we can break down the solution into clear steps:

### Step-by-Step Solution:

1. **Understanding Moissan's Method**:
- Moissan's method is a technique used for the preparation of fluorine gas. It involves electrolysis of a mixture of hydrofluoric acid (HF) and potassium fluoride (KF) in a molten state.

**Hint**: Recall the purpose of Moissan's method and its application in fluorine preparation.

2. **Identifying the Electrodes**:
- In this method, specific materials are used for the electrodes. The electrodes must be able to withstand the corrosive nature of the electrolyte and the high temperatures involved in the process.

**Hint**: Think about materials that are resistant to corrosion and can conduct electricity well.

3. **Electrode Configuration**:
- The cathode is the negative electrode where reduction occurs, while the anode is the positive electrode where oxidation occurs. In Moissan's method, the anode is where fluorine gas is liberated.

**Hint**: Remember the definitions of anode and cathode in electrochemical cells.

4. **Materials Used for Electrodes**:
- The electrodes used in Moissan's method include Platinum, Iridium, and their alloys. These materials are chosen due to their stability and ability to conduct electricity without reacting with the electrolyte.

**Hint**: Consider the properties of Platinum and Iridium that make them suitable for high-temperature electrolysis.

5. **Conclusion**:
- Therefore, the electrodes used in Moissan's method are Platinum, Iridium, and their alloys.

**Hint**: Summarize the key points about the electrode materials and their roles in the electrolysis process.

### Final Answer:
The electrodes used in Moissan's method are Platinum, Iridium, and Alloy.