Question

The following sketch illustrates the process of conversion of Alumina to Aluminium:

1. Name the constituent of the electrolyte mixture which has a divalent metal in it.
2. Name the powdered substances ‘X’ sprinkled on the surface of the electrolyte mixture.
3. What is the name of the process?
4. Write the reactions taking place at the electrodes ‘Y’ (anode) and ‘Z’ (cathode), respectively.

Answer 1

1. The electrolytes used are molten alumina, cryolite and fluospar.
2. Powdered coke layer (X).
3. Hall Heroult process
4. Cathode (Z): \[\ce{Al^{3+} + 3e^{-} -> Al}\]
   Anode (Y): \[\ce{C + 2O^{2+} -> CO_2 + 4e^{-}}\]