WAEC Chemistry 2024 Paper

Concept:Electrolysis of concentrated sodium chloride solution using inert carbon electrodes produces sodium hydroxide in the solution.Explanation:Concentrated $\mathrm{NaCl}$ contains $\mathrm{Na^+}$, $\mathrm{Cl^-}$, $\mathrm{H^+}$ and $\mathrm{OH^-}$ ions.At the cathode, water is reduced: $2\mathrm{H_2O} + 2e^- \rightarrow \mathrm{H_2} + 2\mathrm{OH^-}$.At the anode, chloride ions are oxidized: $2\mathrm{Cl^-} \rightarrow \mathrm{Cl_2} + 2e^-$.The $\mathrm{Na^+}$ ions stay in solution with the $\mathrm{OH^-}$ ions formed.Therefore, the solution left behind is sodium hydroxide, $\mathrm{NaOH}$.This is the main product obtained from the electrolysis of brine.Answer:Sodium hydroxide (Option C).