Some Basic Concepts of Chemistry - Result Question 36 — JEE PYQ Chapterwise

Solution:

38. The redox reaction involved is :

$\mathrm{H}_2 \mathrm{O}_2+2 \mathrm{I}^{-}+2 \mathrm{H}^{+} \longrightarrow 2 \mathrm{H}_2 \mathrm{O}+\mathrm{I}_2$

If $M$ is molarity of $\mathrm{H}_2 \mathrm{O}_2$ solution, then

$\begin{array}{rlrl} & & 5 M & =\frac{0.508 \times 1000}{254}\left(\because 1 \text { mole } \mathrm{H}_2 \mathrm{O}_2 \equiv 1 \mathrm{~mole} \ \mathrm{H}_2 \mathrm{O}_2\right) \\ \Rightarrow \quad & M & =0.4 $\begin{array}

Also, $n$-factor of $\mathrm{H}_2 \mathrm{O}_2$ is 2, therefore normality of $\mathrm{H}_2 \mathrm{O}_2$ solution is 1.6 N .

$\Rightarrow$ Volume strength $=$ Normality $\times 5.6=0.8 \times 5.6=4.48 \mathrm{~V}$