Anhydrous copper sulphate is colourless, but hydrated copper sulphate is blue. Explain ?

Explanation

In anhydrous copper sulphate, the splitting is very less. It absorbs energy in infrared region. It is colourless.
In hydrated copper sulphate, water molecules are present in the coordination sphere. The splitting of d-orbitals is reasonably increased. If it absorbs energy in visible region of light. Hence it is exbibit colour.