Some Basic Concepts of Chemistry 2 Question 35
35. To a $25 \mathrm{~mL} \mathrm{H}{2} \mathrm{O}{2}$ solution, excess of acidified solution of potassium iodide was added. The iodine liberated required $20 \mathrm{~mL}$ of $0.3 \mathrm{~N}$ sodium thiosulphate solution. Calculate the volume strength of $\mathrm{H}{2} \mathrm{O}{2}$ solution.
(1997, 5M)
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Solution:
- Meq of $\mathrm{H}{2} \mathrm{O}{2}=$ Meq of $\mathrm{I}{2}=$ Meq of $\mathrm{Na}{2} \mathrm{~S}{2} \mathrm{O}{3}$
If $\mathrm{N}$ is normality of $\mathrm{H}{2} \mathrm{O}{2}$, then
$$ \begin{aligned} & & N \times 25 & =0.3 \times 20 \ \Rightarrow & & N & =0.24 \end{aligned} $$
$\Rightarrow$ Volume strength $=N \times 5.6=1.334 \mathrm{~V}$
