van Arkel method of purification of metals involves converting the metal to:

Options

A. Volatile enough stable compound
B. Volatile unstable compound
C. Non-volatile stable compound
D. None of these

Answer

### Step-by-Step Solution:

1. **Understanding the Van Arkel Method**: The Van Arkel method is a technique used for the purification of certain metals. It is particularly effective for metals that can form stable volatile compounds.

2. **Conversion to a Compound**: In this method, the metal is converted into a stable volatile compound. This is a crucial step because the volatility of the compound allows for easier separation and purification.

3. **Example of the Process**: For instance, nickel can be treated with carbon monoxide to form nickel tetracarbonyl (Ni(CO)₄). This reaction occurs at approximately 350 K. The formation of this volatile compound is essential for the purification process.

4. **Separation of the Metal**: Once the metal is converted into its volatile compound, the next step involves heating the compound. Upon heating, the compound decomposes, releasing the pure metal and leaving behind any impurities.

5. **Conclusion**: Therefore, the Van Arkel method of purification of metals involves converting the metal to a stable volatile compound.

### Final Answer:
The Van Arkel method of purification of metals involves converting the metal to a stable volatile compound.

---