To lowering the melting point which compound is used in extraction of aluminium?

Answer

To solve the question regarding which compound is used to lower the melting point in the extraction of aluminum, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Extraction Process**:
- Aluminum is extracted from its ore, bauxite, which is primarily composed of aluminum oxide (Al₂O₃). The extraction process involves electrolysis.

2. **Identify the Melting Point Issue**:
- Aluminum oxide has a very high melting point, approximately 2000 degrees Celsius. This high melting point makes the extraction process costly and energy-intensive.

3. **Research Compounds Used to Lower Melting Point**:
- To facilitate the electrolysis process, it is necessary to lower the melting point of aluminum oxide. This is achieved by adding certain compounds.

4. **Identify the Compounds**:
- The compounds commonly used to lower the melting point of aluminum oxide during the extraction process are cryolite (Na₃AlF₆) and fluorspar (CaF₂). These compounds not only lower the melting point but also enhance the electrical conductivity of the mixture.

5. **Conclusion**:
- Therefore, the compound used to lower the melting point in the extraction of aluminum is **cryolite** (and fluorspar).

### Final Answer:
Cryolite (Na₃AlF₆) is used to lower the melting point in the extraction of aluminum.

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