Question

The colour of $KMn{O}_4$ is due to:

• A. $M\to L$ charge transfer transition
• B. $d-d$ transition
• C. $L\to M$ charge transfer transition
• D. $\sigma -{\sigma }^{\ast }$ transition

Answer 1

Answer: (A)

$M\to L$ charge transfer transition

The deep purple color of ${KMnO}_4$

$\to$ is not due to $d-d$ transition

$\to$ due to change transfer (from $O$ to $Mn$) reduced the oxidation state of $Mn$ from $+7$ to $+6$ momentarily.