Key reactions in Hall-Héroult aluminium extraction Steps:

• Recall aluminium extraction uses electrolysis of Al₂O₃ with carbon anodes, not direct carbon reduction.
• Check reaction 1: Represents electrolytic decomposition at cathode (2Al₂O₃ → 4Al + 3O₂, adjusted for balance), producing aluminium.
• Check reaction 2: Overall process where anode carbon reacts with oxygen to form CO₂ (Al₂O₃ + 3C → 2Al + 3CO₂).
• Check reaction 3: Incorrect, as it produces CO instead of CO₂ and has unbalanced atoms (left: 4Al, right: 2Al).

Why B is correct:

• B includes reactions 1 (cathode electrolysis) and 2 (overall carbon-involved reduction), matching the Hall-Héroult process formula.

Why the others are wrong:

• A omits reaction 2, ignoring carbon's role in oxygen consumption.
• C includes incorrect reaction 3, which misrepresents anode product and stoichiometry.
• D includes all, but reaction 3 is invalid.

Final answer: B