Al ₂ O ₃ is reduced by electrolysis at low potentials and high currents. If 4.5 10^4 ~A of current is passed through molten Al ₂ O ₃ for 6 ~h , what mass of aluminium is produced? (Assume 100 % current efficiency, at. mass of Al =27 ~g ~mol ⁻¹ )

Step-by-step solution

Al ₂ O ₃ ionises as, Al ₂ O ₃ cathode 3+ + array r AlO ₃³⁻ anode array At cathode Al ³⁺+ 3 ~F 3 e ⁻ Al 27 ~g Mass of aluminium deposited by 3 ~F of electricity =27 ~g Mass of aluminium deposited by 4.0 10^4 6 3600 C of electricity aligned & = 27 4.0 10^4 6 3600 3 ~F ~g & = 27 4.0 10^4 6 3600 3 96500 ~g & =8.1 10^4 ~g aligned