3. WHAT HAPPENS?
As we know, electrolysis is the passage of electricity through a system containing electrolyte and
electrode to produce a chemical change. Here, the electrolyte contains aqueous sodium chloride solution.
At the anode oxidation of chloride occurs to give chlorine as
2Cl-
(aq) → Cl2(g) + 2e-
At cathode, Hydrogen ions from water molecules are reduced to produce hydrogen gas as
2H2O + 2e- → H2(g) + 2OH-
(aq)
The sodium ions react with hydroxide ions to produce NaOH and the overall electrolytic reaction will
be
2NaCl(aq) + 2H2O → 2NaOH(aq) + Cl2(g) + H2(g)