Aluminium metal is purified by `:`

Options

A. Hoope's process
B. Hall's process
C. Serpeck's process
D. Baeyer's process

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the process used for the purification of aluminium metal.

2. **Identifying the Options**: The options provided are:
- 1st: Hoof's process
- 2nd: Hall's process
- 3rd: Serpac's process
- 4th: Baer's process

3. **Analyzing the Processes**:
- **Hall's Process**: This is primarily used for the extraction of aluminium from its ore, bauxite (Al2O3·H2O), through electrolysis.
- **Serpac's Process**: This is not a commonly recognized process in the context of aluminium purification.
- **Baer's Process**: This is also not widely recognized for aluminium purification.
- **Hoof's Process**: This process is mentioned as a method for obtaining high-purity aluminium.

4. **Choosing the Correct Process**: Based on the information, Hoof's process is specifically mentioned as a method for purifying aluminium metal to a very high purity level (about 99%).

5. **Conclusion**: Therefore, the correct answer is that aluminium metal is purified by Hoof's process.

**Final Answer**: Aluminium metal is purified by Hoof's process.

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