Question

(a) For the reduction of metal oxide, suggest a reducing agent other than carbon.
(b) Explain why, an aqueous solution of sodium chloride is not used for the electrolytic extraction of sodium metal.

Answer 1

(a) Aluminium (Al) can be used as a reducing agent for the reduction of a metal oxide. This is generally used for reducing metal oxides such as manganese dioxide (${\mathrm{MnO}}_2$).

(b) If an aqueous solution of sodium chloride is used in electrolysis, sodium metal, formed at cathode, will immediately react with water in the aqueous solution to form sodium hydroxide because sodium is a highly reactive metal. Hence, it is important to use molten sodium chloride and not its aqueous solution in electrolytic extraction.