Which method is not correct given for refining of crude metals ?

Options

A. Distillation : zinc and mercury
B. Liquation : tin
C. van Arkel : Zirconium
D. Mond process : lead

Answer

To determine which method is not correct for the refining of crude metals, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Distillation**:
- Distillation is a method used for refining metals that have low boiling points and are volatile.
- **Example**: Zinc and Mercury are metals that can be refined using distillation due to their low boiling points.

**Hint**: Distillation is suitable for metals that are volatile and have low boiling points.

2. **Understanding Liquation**:
- Liquation is a refining method used for metals that have low melting points and are easily fusible.
- **Example**: Tin is a metal that can be refined using liquation, along with others like lead and bismuth.

**Hint**: Liquation is effective for metals that melt easily.

3. **Understanding the Van Cycle**:
- The Van cycle is a process used for the purification of Zirconium.
- In this method, impure zirconium reacts with iodine at a specific temperature to form zirconium iodide, which is then further heated to obtain pure zirconium.
- **Temperature**: The reaction occurs at 575 K and is followed by heating to 875 K.

**Hint**: The Van cycle is specifically for refining zirconium.

4. **Understanding the Monde Process**:
- The Monde process is a method used for the purification of Nickel.
- In this process, crude nickel reacts with carbon monoxide at a certain temperature to form nickel carbonyl, which is then decomposed to yield pure nickel.
- **Temperature**: The reaction occurs at approximately 373 K and is followed by heating to 475 K.

**Hint**: The Monde process is not applicable to lead; it is specifically for nickel.

5. **Conclusion**:
- After analyzing all the options, we find that:
- Option 1 (Distillation for Zinc and Mercury) is correct.
- Option 2 (Liquation for Tin) is correct.
- Option 3 (Van cycle for Zirconium) is correct.
- **Option 4 (Monde process for Lead)** is incorrect as the Monde process is used for nickel, not lead.

Thus, the method that is not correct for refining of crude metals is **Option 4: Monde process for Lead**.

### Final Answer:
**Option 4: Monde process for Lead is not correct.**