Chemistry - Redox Reactions Question with Solution | TestHub

The redox changes are
${\text{Mn}}^{+7}+5{\text{e}}^{-}\to {\text{Mn}}^{2+}$
${\left({\text{C}}^{3+}\right)}_2\to 2{\text{C}}^{4+}+2{\text{e}}^{-}$
$\because \text{meq. of oxalate ion=meq}{\text{. of KMnO}}_4$
$\left(\mathrm{w}/\mathrm{E}\right)\times 1000=90\times \left(1/20\right)$
Or$\left(\frac{\text{w}}{88/2}\right)\times 1000=\frac{9}{2}\left(\because {\text{E}}_{{\text{C}}_2{\text{O}}_4^{-2}}=\frac{88}{2}\right)$
or${\text{w}}_{{\text{C}}_2{\text{O}}_4^{-2}}=0.198\text{g}$
$\therefore$% of oxalate in sample$=(0.198\times 100)/0.3=66\%$