Extracting aluminium using electrolysis

Question 1

How is aluminium extracted from aliumunim oxide using electroylsis

Answer 1

cryolite is added to lower boiling point of aluminium oxide which reduces energy costs, the mixture is molten which allows ions to freely move and carry a charge, negative oxide ions are attracted to the anode where oxygen is discharged, positive aluminium ions are attracted to the cathode where aluminium is deposited, carbon electrodes reacts with oxygen forming CO2 so needs to be replaced

Question 2

Oxidation occurs at the cathode or anode

Answer 2

anode as it loses electrons

Question 3

Reduction occurs at the cathode or anode

Answer 3

cathode as it gains electrons

Question 4

Half equation for the anode during extraction of aluminium from aluminium oxide using electrolysis

Answer 4

2O^2- - 4e^- -> O2

6O^2- - 12e^- -> 3O2

Question 5

Half equation for the cathode during extraction of aluminium from aluminium oxide using electrolysis

Answer 5

Al^3+ + 3e^- -> Al

4Al^3+ + 12e^- -> 4Al