Question

What happens when iron nails are put into copper sulphate solution?

Answer 1

When iron nails are put into copper sulphate solution, the blue colour of copper sulphate fades gradually to green due to the formation of ferrous sulphate and the reddish-brown copper metal is deposited on the iron nails.
CuSO₄(aq) + Fe(s) $\to$ FeSO₄(aq) + Cu(s)