Question

Explain why blue colour of copper sulphate solution in discharge when iron filing are add to it

Answer 1

Iron being more reactive displaces copper from it's solution and forms iron sulphate while Cu is deposited on iron

Fe + CuSO4 --> FeSO4 + Cu

Answer 2

because iron have more powerful as well as copper it displaced copper from copper sulphate solution and this type of reaction know as displacement