Question

Why does the colour of copper sulphate solution change when an iron nail is dipped in it?​

Answer 1

Answer:

Iron lies above in the reactivity series and thus more reactive than copper. As a result, the more reactive metal (iron) displaces a less reactive metal (copper) from its salt solution (copper sulphate solution). Hence, the change in color.

Answer 2

When an iron nail immersed in the solution of copper sulphate than iron displaces copper from the solution of copper sulphate because iron is more reactive than copper. Therefore copper sulphate solution colour changes from blue to pale green.

Reaction

CuSO4 (aq) + Fe (s) → FeSO4 (aq) + Cu (s)