Question

The following sketch represents the electroplating of an Iron cup with Nickel metal.

Study the diagram and answer the following questions:

1. During electroplating, the iron cup is placed at the cathode. Why?
2. Name the ion that must be present in the electrolyte.
3. State one condition that is necessary to ensure that the deposit is smooth, firm and even.
4. Write the reaction taking place at the cathode.
5. What change would you observe at the anode?

Answer 1

1. In electroplating, the iron cup is put at the cathode because the cathode is a negative terminal that attracts metals that are positively charged. This leads to the reduction and formation of metal ions.
2. The electrolyte used is a water-based solution of \[\ce{NiSO4}\], so the ions formed are \[\ce{Ni^{2+}, H+, SO_4^{2−}, OH−}\].
3. To ensure smooth deposition, current should be passed slowly and over a longer period of time.
4. Cathode: \[\ce{Ni^{2+} + 2e^- -> Ni}\] (Reduction)
5. The anode, a Ni plate, is etched after the Ni ions finish in the electrolyte.