Question

1 mole of equimolar mixture of $( Fe )_{2}\left(\left(( C )_{2}( O )_{4}\right)\right)_{3}$ and $FeC _{2} O _{4}$ requires $X$ moles of $KMnO _{4}$ in acid medium for complete reaciton. The value of $X$ is:

• A. 0.9
• B. 0.6
• C. 1.2
• D. 0.8

Answer 1

Answer: (A)

$\mathrm{Fe}_2\left(\mathrm{C}_2 \mathrm{O}_4\right)_3 \longrightarrow 2 \mathrm{Fe}^{3+}+6 \mathrm{CO}_2+6 \mathrm{e} \quad($ n Factor $=6)$ $\mathrm{Fe}\left(\mathrm{C}_2 \mathrm{O}_4\right) \quad \longrightarrow \quad \mathrm{Fe}^{3+}+2 \mathrm{CO}_2+3 \mathrm{e} \quad($ n Factor $=3)$
Meqs of $\left[\mathrm{Fe}_2\left(\mathrm{C}_2 \mathrm{O}_4\right)_3+\mathrm{Fe}\left(\mathrm{C}_2 \mathrm{O}_4\right)\right]=0.5 \times 6+0.5 \times 3$
$=4.5 \text { Eqs. } $
$ =4.5 \text { Eqs. of } \mathrm{KMnO}_4 $
$ =\frac{4.5}{5}=0.9 \text { moles of } \mathrm{KMnO}_4 $