Question

On immersing the brown coloured iron nails in blue coloured copper sulphate solution, they displace ................. from the copper sulphate solution and their colour becomes .....................

Answer 1

When an iron nail is dipped in the solution of ${CuSO}_4$, it displaces copper from the solution, which gets deposited / precipitated as a red / red-brown residue. Also, the blue colour of the solution gradually fades out. Ultimately in the solution becomes pales green in colour due to the formation of ${FeSO}_4$.