In the context of the Hall-Heroult process for the extraction of `Al`, which of the following statements is false ?

Options

A. `Al_(2)O_(3)` is mixed with `CaF_(2)` which lowers the melting point of the mixture and brings conductivity
B. `Al^(3+)` is reduced at the cathode to form Al
C. `Na_(3)AlF_(6)` serves as the electrolyte
D. `CO and CO_(2)` are produced in this process

Answer

To determine which statement is false in the context of the Hall-Heroult process for the extraction of aluminum, we need to analyze each statement provided.

### Step-by-Step Solution:

1. **Understanding the Hall-Heroult Process**:
- The Hall-Heroult process is an electrolytic method used to extract aluminum from its ore, bauxite, primarily in the form of aluminum oxide (Al2O3).

2. **Analyzing the Statements**:
- **Statement 1**: "Al2O3 is mixed with Calcium Fluoride (CaF2), which lowers the melting point of the mixture and brings conductivity."
- This statement is **true**. Calcium fluoride is indeed added to lower the melting point and increase the conductivity of the electrolyte.

- **Statement 2**: "Al3+ is reduced at the cathode to form Al."
- This statement is also **true**. In the electrolysis process, aluminum ions (Al3+) gain electrons (are reduced) at the cathode to form aluminum metal (Al).

- **Statement 3**: "Na3AlF6 serves as the electrolyte."
- This statement is **false**. While Na3AlF6 (cryolite) is used in the process, it is not the only component of the electrolyte. The electrolyte consists of a mixture of Al2O3, CaF2, and Na3AlF6.

- **Statement 4**: "CO and CO2 are produced in this process."
- This statement is **true**. During the electrolysis, oxygen is produced at the anode, which reacts with the carbon anodes to form carbon monoxide (CO) and carbon dioxide (CO2).

3. **Conclusion**:
- The false statement among the options is **Statement 3**. While Na3AlF6 is part of the electrolyte, it is not the sole component, as other substances are also mixed in.

### Final Answer:
The false statement is: **"Na3AlF6 serves as the electrolyte."**