In the context of the Hall-Heroult process for the extraction of Al

• Isolation Metals

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

1. Al₂O₃ is mixed with CaF₂ which lowers the melting point of the mixture and brings conductivity
2. Al³⁺ is reduced at the cathode to form Al
3. Na₃AlF₆ serves as the electrolyte
4. CO and CO₂ are produced in this process

Solution

In Hall-Heroult process,

2 Al₂O₃ + 3 C → 4 Al + 3CO₂

Oxygen liberated at anode reacts with carbon anode to give CO and CO₂.

Na₃AlF₆ (cryolite) or CaF₂ is mixed with purified Al₂O₃ to lower the melting point for easier electrolysis.

The correct option is C.