Question

Aluminium is extracted from alumina (Al₂O₃) by electrolysis of a molten mixture of ______.

Options

• Al₂O₃ + HF + NaAIF₄

• Al₂O₃ + CaF₂ + NaAIF₄

• Al₂O₃ + Na₃AIF₆ + CaF₂

• Al₂O₃ + KF + Na₃AIF₅

Answer 1

Aluminium is extracted from alumina (Al₂O₃) by electrolysis of a molten mixture of Al₂O₃ + Na₃AIF₆ + CaF₂.

Explanation:

Aluminium is extracted by electrolysis of molten alumina. Pure Al₂O₃ has a very high melting point, so it is mixed with Cryolite (Na₃AlF₆), which lowers the melting point and increases conductivity. Fluorspar (CaF₂) also helps to lower the melting point.