The major role of flourspar, `CaF_(2)` which is added in small amount in the electrolytic reduction of `Al_(2)O_(3)` dissolved on fused cryolite in fused cryolite is

Options

A. As a catalyst
B. To make the used mixture very conducting
C. To increase the temperature of the melt
D. To decrease the rate of oxidation of carbon of carbon at the anode

Explanation

To solve the question regarding the role of flourspar (CaF₂) in the electrolytic reduction of Al₂O₃ dissolved in fused cryolite, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding the Problem**:
- The question asks about the role of flourspar (CaF₂) when added to the electrolytic reduction process of aluminum oxide (Al₂O₃) in fused cryolite.

2. **Identifying the Challenges with Al₂O₃**:
- Pure aluminum oxide (Al₂O₃) has a very high melting point, approximately 2000°C, which makes it difficult to process.
- Additionally, Al₂O₃ has low electrical conductivity, which is essential for the electrolytic reduction process.

3. **Role of Fused Cryolite**:
- Cryolite (Na₃AlF₆) is used as a solvent for Al₂O₃ to lower its melting point and improve conductivity. However, adding flourspar (CaF₂) further enhances these properties.

4. **Effects of Adding Flourspar (CaF₂)**:
- **Lowering Melting Point**: Flourspar helps to reduce the melting point of the mixture from around 2000°C to approximately 900°C, making the process more feasible.
- **Increasing Electrical Conductivity**: The addition of flourspar increases the electrical conductivity of the molten mixture, which is crucial for the electrolytic reduction to occur efficiently.

5. **Conclusion**:
- The major role of flourspar (CaF₂) in this process is to **increase the electrical conductivity** of the mixture and **reduce the melting point** of Al₂O₃, facilitating the electrolytic reduction.

### Final Answer:
The major role of flourspar (CaF₂) added in small amounts during the electrolytic reduction of Al₂O₃ dissolved in fused cryolite is to **increase the electrical conductivity** of the mixture.