Si  is refined by

Options

A. Vapour phase refining
B. Zone refining
C. Liquation
D. van Arkel method

Answer

**Step-by-Step Solution:**

1. **Understanding Refining**: Refining is the process used to obtain pure metals from impure or crude materials. This is achieved through various methods that separate impurities from the desired metal.

2. **Identifying the Methods**: The question presents four options for refining silicon:
- Vapor phase refining
- Zone refining
- Liquation
- Van-Ankle method

3. **Analyzing Each Method**:
- **Vapor Phase Refining**: This method is generally used for metals that can be converted into gaseous compounds and then back to solid form. It is not commonly used for silicon.
- **Zone Refining**: This is a technique particularly effective for purifying semiconductors like silicon and germanium. It works on the principle that impurities are more soluble in the molten state than in the solid state.
- **Liquation**: This method is used for separating metals based on differences in melting points, but it is not suitable for silicon.
- **Van-Ankle Method**: This is not a standard method for refining silicon.

4. **Conclusion**: Given that zone refining is specifically designed for semiconductors and is based on the solubility of impurities in the molten state, it is the most appropriate method for refining silicon.

5. **Final Answer**: Silicon is refined by **Zone Refining**.

---