Question

what happens when an iron nail is kept immersed in copper sulphate solution with experiment

Answer 1

The solution becomes light green incolour and the iron nail gets coated

Answer 2

In this case, iron, being more reactive than copper, will displace it from the solution. That is, ferrous ions or Fe(II) will go into the solution, while curic or Cu(II) will be deposited onto the nail. This cause the solution color to change from blue to green.