An aqueous solution of sodium sulphate () is electrolysed using completely inert platinum electrodes — Electrochemistry Chemistry Question

💡 Solution & Explanation

In aqueous $Na_2SO_4$, water is easier to reduce than $Na^+$ and easier to oxidize than $SO_4^{2-}$. Cathode reaction: $2H_2O + 2e^- \rightarrow H_2(g) + 2OH^-(aq)$ (Local pH increases). Anode reaction: $2H_2O \rightarrow O_2(g) + 4H^+(aq) + 4e^-$ (Local pH decreases). Since $H^+$ and $OH^-$ are produced in stoichiometric equivalents ($4H^+$ for every $4OH^-$ generated by $4e^-$), the bulk mixed solution remains neutral.