Question

Why is the color of potassium permanganate pink?

Answer 1

We need to know that the potassium permanganate is in inorganic salt which is pink in color having chemical formula $KMn{O_4}$.Potassium permanganate is widely used in chemical industry and laboratories as a strong oxidizing agent, and also as a medication for dermatitis and for cleaning wounds.

Complete answer:
We have to know that the color of $KMn{O_4}$ is due to transitions of charge transfer by the absorption of visible light. Metal ions possess the electron in $KMn{O_4}$ and thus the transition of charge takes place from ${O^-}$ to $M{n^ + }$.Undiluted permanganate potassium has a striking purple tint, but pink should be a diluted solution. Potassium permanganate must be filtered because burns can be caused by an undiluted solution. The color of $KMn{O_4}$ is due to charge transfer transitions by absorption of visible light. $KMn{O_4}$ has a deep purple color. The metal ions in $KMn{O_4}$ contains d electron and, therefore, charge transfer occurs from ${O^-}$ to $M{n^ + }$. In fact, the lowest energy $L \to M$ charge transfer is due to the transition of a nonbonding 2p oxygen electron to the unoccupied molecular orbital level of a tetrahedral compound. As the positive charge on a metal ion increases, its electro negativity also increases. Therefore, a transfer of charge from ${O^-}$ to $M{n^ + }$ ions may occur in the lower energy region (visible region).

Note:
We have to know that the dilute solutions of $KMn{O_4}$ convert alkenes into diols (glycols). This behavior is also used as a qualitative test for the presence of double or triple bonds in a molecule, since the reaction decolorizes the initially purple permanganate solution and generates a brown precipitate $\left( {Mn{O_2}} \right)$. Manganese belongs to the d block element that is a transition metal.