In the electrolysis of alumina it is mixed with cryolite `(Na_(3)AlF_(6))` and Fluorspar `(CaF_(2))` in the ratio `20:40:20`. The function of cryolite and fluorspar is

Options

A. To dissolve alumina
B. To increase ionization of alumina
C. To increase the fusion temperature of alumina
D. To decrease the fusion temperature of alumina and to make it good conductor of electricity.

Explanation

To solve the question regarding the function of cryolite `(Na3AlF6)` and fluorospar `(CaF2)` in the electrolysis of alumina, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Electrolysis of Alumina**:
- Alumina, represented as `Al2O3`, is the primary source of aluminum. However, in its pure form, it is a poor conductor of electricity.

2. **Identifying the Problem with Pure Alumina**:
- The melting point of alumina is very high, approximately 2072°C (or 2345 K). This high melting point makes it difficult to conduct electrolysis efficiently.

3. **Role of Cryolite (Na3AlF6)**:
- Cryolite is added to the alumina to lower its melting point. When mixed with alumina, cryolite helps to reduce the melting point significantly, allowing the electrolysis process to occur at a more manageable temperature.

4. **Role of Fluorspar (CaF2)**:
- Fluorspar, or calcium fluoride, also contributes to lowering the melting point and improving the fluidity of the molten mixture. This helps in the efficient separation of aluminum during the electrolysis process.

5. **Resulting Mixture**:
- The mixture of alumina with cryolite and fluorspar in the ratio of 20:40:20 effectively lowers the melting point to around 1140°C (or 1413 K), making it easier to conduct electrolysis.

6. **Conclusion**:
- The primary functions of cryolite and fluorospar in the electrolysis of alumina are to lower the melting point of alumina and to enhance its conductivity, facilitating the electrolysis process to produce aluminum efficiently.

### Final Answer:
The functions of cryolite `(Na3AlF6)` and fluorospar `(CaF2)` in the electrolysis of alumina are to lower the melting point of alumina and to improve its conductivity, allowing for efficient electrolysis.

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