Question

When $KMn{O}_4$ is reduced with oxalic acid in acidic solution, the oxidation number of Mn changes from.

• A. $7$ to $2$
• B. $7$ to $4$
• C. $7$ to $6$
• D. $6$ to $2$

Answer 1

Answer: (A)

$7$ to $2$

In acidic medium it reacts as follows:

$Mn{O_4}^{-}+8H^{+}+5e^{-}\to {Mn}^{+2}+4H_{2}O$

So oxidation state of $Mn$ changes from +7 to +2.