Question

The reddish brown deposit formed on iron nails kept in a solution of copper sulphate is

1. Cu₂O
2. Cu
3. CuO
4. CuS

Answer 1

(b) Cu.

When iron nails are kept in a copper sulphate solution, the more reactive element iron displaces the less reactive element copper from copper sulphate and forms ferrous sulphate.

Fe_(s) + CuSO_4(aq) → FeSO_4(aq) + Cu_(s)