In the electrolytic reduction of pure `Al_2O_3`. Fluorspar `(CaF_2)` is added to

Options

A. Reduce the melting temperature of the mixture
B. Improve the electrical conductivity of the melt
C. Reduce `Al_2O_3`
D. Both (1) and (2)

Answer

To solve the question regarding the addition of fluorspar (CaF2) in the electrolytic reduction of pure Al2O3, we can break down the reasoning step by step.

### Step-by-Step Solution:

1. **Understanding the Process**:
- The electrolytic reduction of Al2O3 (alumina) is used to extract aluminum. This process requires high temperatures to melt the alumina for effective electrolysis.

2. **Role of Fluorspar (CaF2)**:
- Fluorspar, or calcium fluoride (CaF2), is added to the alumina during the electrolysis process.

3. **Reducing Melting Temperature**:
- One of the primary reasons for adding CaF2 is to lower the melting temperature of the alumina mixture. Pure Al2O3 has a high melting point (around 2050°C), and the addition of CaF2 helps to reduce this temperature significantly, making the process more energy-efficient.

4. **Improving Electrical Conductivity**:
- Besides lowering the melting point, CaF2 also improves the electrical conductivity of the molten mixture. A good electrical conductor is essential for the electrolysis process to ensure that the electric current can flow easily through the melt, facilitating the reduction of aluminum ions.

5. **Conclusion**:
- Therefore, the addition of CaF2 serves two main purposes: (a) to reduce the melting temperature of the mixture and (b) to improve the electrical conductivity of the melt.

6. **Correct Answer**:
- Based on the above reasoning, the correct answer to the question is option D: both (a) and (b) are correct.