Question

$0.2$ g of a sample of $H_2{O}_2$ require $10$ mL of $1$ N$KMn{O}_4$ in a titration in the presence of $H_{2}S{O}_4$. Purity of $H_2{O}_2$ is :

• A. $25\%$
• B. $85\%$
• C. $65\%$
• D. None of these

Answer 1

The correct option is B $85\%$

Let the sample contain $x$ g of $H_2{O}_2$.
Meq. of $H_2{O}_2$ = Meq. of $KMn{O}_4$
$x/17=0.01⟹x=0.17$ g
So, purity of sample $=\frac{0.17\times 100}{0.2}=85$ %.