Question

Explain why, an aqueous solution of sodium chloride is not used for the electrolytic extraction of sodium metal.

Answer 1

An aqueous solution of sodium chloride cannot be used because water molecules are preferentially reduced over sodium ions at the cathode. Water has a much higher reduction potential (is easier to reduce) than Na⁺ ions. Therefore, hydrogen gas (H₂) is liberated at the cathode instead of sodium metal. To isolate pure sodium metal, molten sodium chloride must be used so that Na⁺ is the only cation available for reduction.