Question

Which of the following compounds has color but not unpaired electrons?

• A. $Mn{O}_2$
• B. $KMn{O}_4$
• C. $K_{2}Mn{O}_4$
• D. $MnC{l}_2$

Answer 1

The correct option is B $KMn{O}_4$

$KMn{O}_4$ is purple color but Mn is in +7 oxidation state ($d^0$ configuration). The color is not due to d-d transition but it is due to charge transfer transition from ligand (oxygen) to metal (manganese).