Question

Which suitable cathode is used in the electroplating of an iron bell with nickel?

Answer 1

Electroplating

• Electroplating involves electrolytic deposition of superior metal's thin film on a metallic object made up of inferior metal.
• Superior metals are those metal which do not corrode.
• Metals which easily undergo corrosion such as iron, copper, etc. are known as inferior metals.

In electroplating, article to plated with is used as cathode. So, in the electroplating of an iron bell with nickel, iron bell is made as cathode and plate or rod of pure nickel is made as anode. Nickel sulfate is used as an electrolyte.

Reaction during electrolysis:

$$\begin{gathered} {\mathrm{NiSO}}_4\rightleftharpoons {\mathrm{Ni}}^{2+}+{{\mathrm{SO}}_4}^{2-} \\ {\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{H}}^{+}+{\mathrm{OH}}^{-} \end{gathered}$$

Reaction at cathode:

${\mathrm{Ni}}^{2+}+2{\mathrm{e}}^{-}\rightleftharpoons \mathrm{Ni}$

Reaction at anode:

$\mathrm{Ni}-2{\mathrm{e}}^{-}\rightleftharpoons {\mathrm{Ni}}^{2+}$

This, iron bell itself is used as cathode for electroplating with nickel.