The colour of KMnO4 is due to

Answer : The colour of KMnO4 comes from charge transfer transitions caused by visible light absorption.

The colour of KMnO4 is dark purple. Because the metal ions in KMnO4 have a d- electron, charge transfer from O– to Mn+ happens. The transition of a nonbonding 2p oxygen electron to the vacant molecular orbital of a tetrahedral complex causes the lowest energy Ligand to Metal  charge transfer.