Aluminium oxide may be electrolysed at 1000 °C to furnish aluminium metal.
The cathode reaction is  Al³⁺ + 3e^- → Al.
To prepare 5.12 kg of aluminium metal by this method would require:
(Atomic mass = 27 amu; 1 faraday=96,500 Coulombs)

1. 5.49×10¹ C of electricity
2. 5.49×10⁴ C of electricity
3. 1.83×10⁷ C of electricity
4. 5.49×10⁷ C of electricity