Question

How many moles of $KMn{O}_4$ are needed to oxidise a mixture of 1 mole each of $FeS{O}_4$ and $Fe{C}_2{O}_4$ in acidic medium?

• A. 4/5
• B. 5/4
• C. 3/4
• D. 5/3

Answer 1

Answer: (A)

$\text{n}\text{o}.\text{o}\text{f}\text{e}\text{q}\text{u}\text{i}\text{v}\text{a}\text{l}\text{e}\text{n}\text{t}\text{s}=\text{m}\text{o}\text{l}\text{e}\text{s}\times \text{n-}\text{f}\text{a}\text{c}\text{t}\text{o}\text{r}$

$\text{n-factor}\text{of}{\left(\text{KMnO}\right)}_4=5\text{(in}\text{acidic}\text{medium)}$

$\text{F}\text{e}\text{S}{\text{O}}_4=1$

$\text{F}\text{e}{\text{C}}_2{\text{O}}_4=3$

Number of equivalents of $KMn{O}_4$

= Number of equilvanets of $FeS{O}_4+$ Number of equivalents of $Fe{C}_2{O}_4$

$x\times 5=1\times 1+1\times 3$

$x=\frac{4}{5}$