Question

The number of moles of $KMn{O}_4$ that will be needed to react completely with one mole of ferrous oxalate in an acidic solution is:

• A. $\frac{3}{5}$
• B. $\frac{2}{5}$
• C. $\frac{4}{5}$
• D. $\frac{1}{5}$

Answer 1

The correct option is A $\frac{3}{5}$

The balanced reaction is
$2KMn{O}_4+5C_2{O}_4^{2-}+16H^{+}\to 2M{n}^{2+}+2K^{+}+10C{O}_2+8H_{2}O$
and
$KMn{O}_4+5F{e}^{2+}+8H^{+}\to K^{+}+5F{e}^{3+}+M{n}^{2+}+4H_{2}O$
5 moles of $Fe{C}_2{O}_4$ require 3 moles of $KMn{O}_4$
1 mole of $Fe{C}_2{O}_4$ requires $\frac{3}{5}$ moles of $KMn{O}_4$
We can also solve this by equating equivalents of both the compounds.