Question

$Mn{O}_4^{-}$ is of intense pink colour, though Mn is in $(+7)$ oxidation state. It is due to

• A. oxygen gives colour to it
• B. charge transfer when Mn gives its electron to oxygen
• C. charge transfer when oxygen gives its electron to Mn making it $Mn(+VI)$ hence coloured
• D. none is correct

Answer 1

Answer: (C)

The intense pink colour of $Mn{O}_4^{-}$ is not due to $d-d$ transition but due to charge transfer (from $O$ to Mn) reducing the oxidation state of Mn from $+6$ to $+5$ momentarily.