Question

The number of moles of oxalate ions oxidized by one mole of $Mn{O}_4^{-}$ ion is :

• A. $\frac{1}{5}$
• B. $\frac{2}{5}$
• C. $\frac{5}{2}$
• D. $5$

Answer 1

The correct option is C $\frac{5}{2}$

Reaction of oxalate ions being oxidized by $Mn{O}_4^{-}$ ions is:

$Mn{O}_4^{-}+C_2{O}_4^{2-}\rightleftharpoons M{n}^{+2}+2C{O}_2$

$+7$ $+3$ $+2$ $+4$

$Mn{O}_4^{-}\to M{n}^{+2}$ [Decrease 5]

$C_2{O}_4\to 2C{O}_2$ [Increase 1] $(1\times 2=2increase)$

Final Reaction: $2Mn{O}_4^{-}+5C_2{O}_4^{2-}\rightleftharpoons 2M{n}^{+2}+10C{O}_2$

Therefore, since $2$ moles of $Mn{O}_4^{-}$ oxidize $5$ moles of $C_2{O}_4^{2-}$

So, $1$ mole of $Mn{O}_4^{-}$ will oxidize $\frac{5}{2}$ moles of $C_2{O}_4^{2-}$