Question

The total charge required for the oxidation of two moles of $M{n}_3{O}_4$ into $Mn{O}_4^{2-}$ ions in an alkaline medium is:

• A. 5 F
• B. 10 F
• C. 20 F
• D. None of these

Answer 1

The correct option is C 20 F

To calculate charge required for oxidation,
first we need to balance the equation
as the reaction is in alkaline medium change in oxidation state of Mn = $\frac{+8}{3}$ to +6
$M{n}_3{O}_4\to 3Mn{O}_4^{2-}+10e^{-}$ for balancing O we will add $O{H}^{-}$
$M{n}_3{O}_4+16O{H}^{-}\to 3Mn{O}_4^{2-}+8H_{2}O+10e^{-}$
For 1 mole 10$e^{-}$ are required so for 2 mole 20$e^{-}$ are required.