1. Select the correct statement: a. Colour of the transition metal ions arises due to d-d transition b. Colour of certain oxysalts of transition metals is due to charge transfer c. Both are correct d. None is correct.

Both are correct

Explanation:

Metals of the d-block have five degenerate d orbitals. However, in the presence of ligands, these orbitals are no more degenerate and they split into sets of degenerate orbitals depending on the nature of the ligands and the geometry of the complex formed.

Hence it is possible for electrons to undergo d-d transitions when this occurs leading to the unique color of some transition metal ions.

Also, charge transfer accounts for the color of oxysalts such as KMnO4 where the d-d transition band is weak.