O-LevelChemistryElectrolysis5070/12 · May/June 2014 · Q131 Mark
A concentrated aqueous solution of sodium chloride is electrolysed. What are the equations for the reactions taking place at the cathode (negative electrode) and the anode (positive electrode)?
A2H⁺ + 2e⁻ → H₂ and 2Cl⁻ → Cl₂ + 2e⁻
B2H⁺ + 2e⁻ → H₂ and 4OH⁻ → O₂ + 2H₂O + 4e⁻
CNa⁺ + e⁻ → Na and 2Cl⁻ → Cl₂ + 2e⁻
DNa⁺ + e⁻ → Na and 4OH⁻ → O₂ + 2H₂O + 4e⁻
✓ Correct answer
A: 2H⁺ + 2e⁻ → H₂ and 2Cl⁻ → Cl₂ + 2e⁻
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