Question

Which of the following chemical reactions represents Hall- Heroult Process?

Options

• \[\ce{Cr2O3 + 2Al -> Al2O3 + 2Cr}\]

• \[\ce{2Al2O3 + 3C -> 4Al + 3CO2}\]

• \[\ce{FeO + CO -> Fe + CO2}\]

• \[\ce{2[Au(CN)2]_{(aq)} + Zn_{(s)} -> 2Au_{(s)} + [Zn(CN4)^{2-}]}\]

Answer 1

\[\ce{2Al2O3 + 3C -> 4Al + 3CO2}\]

Explanation:

The Hall–Héroult process is the electrolytic reduction of alumina (Al₂O₃) dissolved in fused cryolite (Na₃AlF₆). During electrolysis, aluminium is deposited at the cathode, and oxygen evolved at the anode reacts with carbon to form CO and CO₂. Hence, the overall reaction is represented as:

\[\ce{2Al2O3 + 3C −> 4Al + 3CO2}\]