Question

When 0.1 mol $Mn{O}_4^{2-}$ is oxidised, quantity of electricity required to completely oxidise $Mn{O}_4^{2-}$ to $Mn{O}_4^{-}$ is

• A. 96500 C
• B. 2 $\times$ 96500 C
• C. 9650 C
• D. 96.50 C

Answer 1

Answer: (C)

The explanation for the correct option

Option(B) 9650 C
1. The oxidation reaction is
$\underset{0.1mol}{\stackrel{+6}{Mn{O}_4^{2-}}}\to \stackrel{+7}{Mn{O}_4^{-}}+\stackrel{e^{-}}{0.1mol}$

2. The oxidation of $Mn{O}_4^{2-}$ requires 1 mole of electrons

3. Hence, 0.1 mole of $Mn{O}_4^{2-}$ requires 0.1 moles of electrons.

4. One faraday of charge is the magnitude of the charge of one mole of electrons.

5. Hence, the quantity of electricity required to completely oxidize $Mn{O}_4^{2-}$ to $Mn{O}_4^{-}$ is
$Q=0.1\times F=0.1\times 96500C=9650C$