Question

why dose the colour of copper sulphate solution change when an iron nail is dipped in it ?

Answer 1

the colour of copper sulphate solution change when an iron nail is dipped in it bcoz iron nail is more reactive than the solution of copper sulphate that's why it's colour changes when iron is dipped in it.

Answer 2

Iron is more reactive than Cupper, so when we dipped an iron mail in it iron displace, Cupper from it's solution and make iron sulphate and gives green colour of the solution.

Fe(s) + CuSO4 -------> FeSO4(aq)+ CuS(s)