The colours of aqueous solutions of $CuSO_4$ and $FeSO_4$ as observed in the laboratory are :

In the laboratory, an aqueous solution of copper sulphate ($CuSO_4$) is characteristically dark blue in colour due to the presence of hydrated copper ions $[Cu(H_2O)_6]^{2+}$. On the other hand, an aqueous solution of ferrous sulphate ($FeSO_4$) is pale green in colour due to the presence of hydrated iron(II) ions $[Fe(H_2O)_6]^{2+}$. Therefore, the correct option is D.

Distractor Analysis:

• Option A is incorrect because it reverses the colours, stating that $CuSO_4$ is pale green and $FeSO_4$ is light blue.
• Option B is incorrect because $FeSO_4$ solution is pale green, not dark green.
• Option C is incorrect because $FeSO_4$ solution is pale green, not dark green.