Vamsi took few wire pieces made up of different metals and placed them in blue solution of copper sulphate.  What will be the changes in the colour of the solutions present in beakers I, II and III.

As iron is more reactive than copper, it displaces copper from copper sulphate solution and green solution of iron sulphate is formed

${\mathrm{Fe}}_{\left(\mathrm{s}\right)}+\underset{\mathrm{Blue}}{{\mathrm{CuSO}}_{4\left(\mathrm{aq}\right)}}\to \underset{\mathrm{Green}}{{\mathrm{FeSO}}_{4\left(\mathrm{aq}\right)}}+{\mathrm{Cu}}_{\left(\mathrm{s}\right)}$

Silver and gold are less reactive than copper.  Therefore silver and gold do not displace copper from copper sulphate solution.  Hence solution remains blue in colour.