Question

When fused sodium chloride is electrolysed, explain exactly what happens at the electrodes and explain how the electricity is conducted ?

Answer 1

When electricity is passed through fused sodium chloride, the electrolysis starts as follows :

NaCl ⇌ Na⁺ + Cl^–

Na⁺ + e^– ⟶ Na (At cathode)

Cl^– – e^– ⟶ Cl

Cl + Cl ⟶ Cl₂ (At anode)

Sodium metal is deposited at cathode, while chlorine gas is liberated at anode. Electricity is conducted with the help of free sodium and chloride ions, which are present in fused sodium chloride.