Question

A dilute aqueous solution of $N{a}_{2}S{O}_4$ is electrolysed using platinum electrodes. The products at the anode and cathode are:

• A. $O_2,H_2$
• B. $S_2{O}_8^{2-},Na$
• C. $O_2,Na$
• D. $S_2{O}_8^{2-},H_2$

Answer 1

The correct option is A $O_2,H_2$

At cathode, water is more easily reduced in comparison to $N{a}^{+}$.
At anode, water is more easily oxidised in comparison to $S{O}_4^{2-}$
The electrode reactions are:
$2H_{2}O+2e^{-}\to H_2\left(g\right)+2O{H}^{-}\text{(cathode )}$
$H_{2}O\to \frac{1}{2}{O}_2\left(g\right)+2H^{+}+2e^{-}\text{(anode)}$