Ncert Exercises & Solutions

CuSO $_{4} 5 H_{2} 0$ is blue in colour while CuSO $_{4}$ is colourless. Why?

In CuSO, :SH,0, water acts as ligand and causes arystal field spliting. Hence, d-d

transition is possible thus CuSO, :SH,0 is coloured. In the anhydrous CuSO

_{4}

due to the
absence of water (ligand), crystal field splitting is not possible and hence, itis colourless.