Brine is a solution of sodium chloride and water. On electrolysis, it gives chlorine (Cl2), hydrogen (H2) and sodium hydroxide (NaOH). At cathode ‌2H+(aq)+2e−→‌
H2
‌ Hydrogen ‌
‌2H2O+2e−→H2+2OH−(aq) At anode 2Cl−→‌
Cl2
‌ Chlorine ‌
+2e− The hydroxide ion, with the unchanged sodium ion, forms NaOH. Na++OH−→‌