Question

5.0 ${cm}^3$ of $H_2{O}_2$ liberates 0.508 g if iodine from an acidified KI solution. The strength of $H_2{O}_2$ solution in term of volume strength at STP is?

• A. 6.48 volumes
• B. 4.48 volumes
• C. 7.68 volumes
• D. None of these

Answer 1

Answer: (B)

4.48 volumes

$H_2{O}_2+2J^{-}\to J_2+2H_{2}O+2H^{+}$

$0.508g$ $J_2$

$n\to \frac{0.508}{254}=0.002$mol

$\therefore 5ml{H}_2{O}_2$ reaction contain $0.002$ mol $H_2{O}_2$

$1L{H}_2{O}_2$ reaction contain $0.002\times \frac{1000}{5}$$=0.4$ mol $H_2{O}_2$

$2H_2{O}_2\rightleftharpoons 2H_2{O}_2+O_2$

$\therefore 0.2$ mol $O_2$ is formed from it.

$\text{Volume strength}=22.4\times 0.2$

$=4.48V$