Key Aspects of Aluminium Extraction by Electrolysis

Steps:

• Recall Hall-Héroult process: Aluminium extracted via electrolysis of Al₂O₃ in molten cryolite (Na₃AlF₆) to lower melting point.
• Verify statement 1: Correct, as electrolyte is Al₂O₃ dissolved in molten cryolite for conductivity.
• Verify statement 2: Correct, carbon (graphite) electrodes used; anodes oxidize, cathode lined with carbon for aluminium deposition.
• Verify statement 3: Incorrect, CO₂ forms at anode (C + O²⁻ → CO₂), not cathode where Al³⁺ + 3e⁻ → Al.

Why A is correct:

• A selects 1 and 2 only, matching the process where cryolite solvent and carbon electrodes are standard, per electrolysis setup reducing Al₂O₃.

Why the others are wrong:

• B includes 3, but CO₂ evolves at anode, not cathode.
• C includes 3 and excludes 1, ignoring correct electrolyte.
• D includes all, but 3 misidentifies gas production site.

Final answer: A