Question

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

Options

• CO and CO₂ are produced in this process.

• Al₂O₃ is mixed with CaF₂ which lowers the melting point of the mixture and brings conductivity.

• Al³⁺ is reduced at the cathode to form Al.

• Na₃AlF₅ serves as the electrolyte.

Answer 1

Na₃AlF₅ serves as the electrolyte.

Explanation:

In the Hall–Héroult process, the electrolyte is a fused mixture of alumina (Al₂O₃), cryolite (Na₃AlF₆), and a small amount of fluorspar (CaF₂). Cryolite (Na₃AlF₆) not Na₃AlF₅ it lowers the melting point of alumina and increases its conductivity. Hence, the statement “Na₃AlF₅ serves as the electrolyte” is false.