Describe how electroplating can be used to achieve the following objectives:
(b) Purify metals
Answers
Answer:
Electroplating is the process of depositing a layer of a metal on a metallic or a nonmetallic electrode by electrolysis in an electrolytic cell.
Let us take an iron spoon which is to be electroplated with copper. For this, we take a copper plate and an iron spoon as electrodes and copper sulphate (CuSO
4
) is taken as an electrolyte. The electrodes are connected through an external circuit as shown in figure. On passing current through the electrolyte, it is decomposed into Cu
2+
and (SO
4
)
2−
ions.
As Cu
2+
ion is positively charged, it moves towards the negative terminal i.e. iron spoon and gets deposited on it. Thus, iron spoon gets plated with copper. There is no scarcity of Cu atoms because the copper atoms go into the solution from the positive terminal i.e. copper plate. This process called electroplating continues until the iron spoon gets coated with copper.