Question

Aqueous solution of nickel sulphate contains $N{i}^{2+}$ and ${S{O}_4}^{2-}$ ions. Which ion moves towards the cathode?

• A. $N{i}^{2+}$
• B. ${S{O}_4}^{2-}$
• C. both A and B
• D. none of these

Answer 1

The correct option is A $N{i}^{2+}$

Reaction at cathode (Reduction)	Reaction at Anode (Oxidation)
Ions at cathode : $N{i}^{2+},H^{+}$ Preferential discharge of $N{i}^{2+}$ ions takes place. $N{i}^{2+}\left(aq\right)+2e^{-}\to N{i}^0\left(s\right)$ Nickel metal deposits on the article. i.e. nail.	Ions at anode : $S{O}_4^{2-},O{H}^{-}$ $N{i}^0\left(s\right)-2e^{-}\to N{i}^{2+}\left(aq\right)$ $N{i}^{2+}$ ions are formed at anode.

None of the above ions discharge at anode ; instead Ni atoms of the anode lose electrons to form $N{i}^{2+}$ ions.