Al2O3 ionises as, Al2O3⇌ cathode 3++AlO33− anode At cathode Al3++3 F3e−⟶27 gAl ∵ Mass of aluminium deposited by 3 F of electricity =27 g ∴ Mass of aluminium deposited by 4.0×104×6×3600C of electricity =3 F27×4.0×104×6×3600 g=3×9650027×4.0×104×6×3600 g=8.1×104 g