Question

$KMn{O}_4$ acts as an oxidising agent and ultimately forms $[Mn{O}_4^{2-},Mn{O}_2,M{n}_2{O}_3]$ and $M{n}^{+2}.$ Then the number of electrons transferred in each case respectively is:

• A. 4, 3, 1, 5
• B. 1, 5, 3, 7
• C. 1, 3, 4, 5
• D. 3, 5, 7, 1

Answer 1

The correct option is C 1, 3, 4, 5

The oxidation number of $Mn$ in $KMn{O}_4,Mn{O}_4^{2-},Mn{O}_2,M{n}_2{O}_3$ and $M{n}^{2+}$ is 7, 6, 4, 3 and 2 respectively.

The number of electrons transferred corresponds to the change in the oxidation number.
So, when $KMn{O}_4$ acts as an oxidising agent and ultimately forms $Mn{O}_4^{2-},Mn{O}_2,M{n}_2{O}_3$ and $M{n}^{+2},$ then the number of electrons transferred in each case are:

7-6=1,
7-4= 3,
7-3= 4,
7-2= 5 respectively.

Hence, (c) is the correct answer.