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

Options

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

Answer

To determine which statement is false regarding the Hall-Heroult process for the extraction of aluminum, we need to analyze each statement based on our understanding of the process.

### Step-by-Step Solution:

1. **Understanding the Hall-Heroult Process**:
- The Hall-Heroult process is the primary method for extracting aluminum from its ore, bauxite. The main components involved are alumina (Al2O3), cryolite (Na3AlF6), and sometimes fluorspar (CaF2).

2. **Analyzing Each Statement**:
- **Statement A**: "Carbon monoxide and carbon dioxide are the two products in this process."
- This statement is **true**. During the process, oxygen produced at the anode reacts with the carbon of the graphite electrodes to form carbon monoxide (CO) and carbon dioxide (CO2).

- **Statement B**: "Al2O3 is mixed with CaF2 which lowers the melting point of the mixture and brings conductivity."
- This statement is **true**. The addition of CaF2 (fluorspar) helps to lower the melting point of the mixture and increases its electrical conductivity.

- **Statement C**: "Al^3+ is used as the cathode to form Al."
- This statement is **true**. In the Hall-Heroult process, aluminum ions (Al^3+) are reduced at the cathode to form aluminum metal.

- **Statement D**: "NH3AlF6 serves as electrolyte."
- This statement is **false**. The electrolyte used in the Hall-Heroult process is a mixture of alumina, cryolite, and sometimes fluorspar, not NH3AlF6.

3. **Conclusion**:
- The false statement among the options provided is **Statement D**: "NH3AlF6 serves as electrolyte."

### Final Answer:
The false statement is **D**: "NH3AlF6 serves as electrolyte."

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