QJEEM15Ch6bc2: JEE Main 2015 Chemistry - Class 12 JEEM15Ch6bc2 Solution: The colour of KMnO 4 is due to :

$$L\to M$$ charge transfer spectra. $$KMn{O}_4$$ is colored because it absorbs light in the visible range of electromagnetic radiation. The permanganate ion is the source of color, as a ligand to metal, $$\left(L\to M\right)$$ charge transfer takes place between oxygen's $$p$$ orbitals and the empty $$d$$-orbitals on the metal. This charge transfer takes place when a photon of light is absorbed, which leads to the purple color of the compound.