In 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 from Al
D. `Na_(3)AlF_6` helps in increasing the melting point of the mixture

Answer

To determine which statement is false regarding the Hall-Heroult process for the extraction of aluminum, let's analyze each of the provided statements step by step.

### Step 1: Understanding the Hall-Heroult Process
The Hall-Heroult process is the primary method for extracting aluminum from its ore, bauxite. The key steps involve:
- Purifying aluminum oxide (Al2O3) from bauxite.
- Dissolving Al2O3 in cryolite (Na3AlF6) to lower its melting point and increase conductivity.
- Electrolyzing the mixture to produce aluminum metal at the cathode and oxygen at the anode.

### Step 2: Analyzing the Statements
1. **Statement 1**: "Cu and CO2 are produced in the process."
- This statement is **false**. While CO2 is produced, copper (Cu) is not a product of the Hall-Heroult process.

2. **Statement 2**: "Al2O3 is mixed with CaF2 which lowers the melting point of the mixture and brings conductivity."
- This statement is **true**. CaF2 (calcium fluoride) is indeed added to the mixture to help lower the melting point and improve conductivity.

3. **Statement 3**: "Al3+ is reduced at the cathode to form aluminum."
- This statement is **true**. The aluminum ions (Al3+) gain electrons at the cathode to form aluminum metal.

4. **Statement 4**: "Na3AlF6 helps in increasing the melting point of the mixture."
- This statement is **false**. Cryolite (Na3AlF6) actually lowers the melting point of the mixture, making this statement incorrect.

### Conclusion
The false statements are:
- **Statement 1**: "Cu and CO2 are produced in the process." (False)
- **Statement 4**: "Na3AlF6 helps in increasing the melting point of the mixture." (False)

### Final Answer
The false statement regarding the Hall-Heroult process is: "Na3AlF6 helps in increasing the melting point of the mixture."

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