How many ' $\mathrm{mL}$ ' of perhydrol is required to produce sufficient oxygen which can be used to…
How many ' $\mathrm{mL}$ ' of perhydrol is required to produce sufficient oxygen which can be used to completely convert $2 \mathrm{~L}$ of $\mathrm{SO}_2$ gas to $\mathrm{SO}_3$ gas?
10 mL
5 mL
20 mL
30 mL
Solution
Perhydrol means $30 \%$ solution of $\mathrm{H}_2 \mathrm{O}_2$. $\mathrm{H}_2 \mathrm{O}_2$ decomposes as
$2 \mathrm{H}_2 \mathrm{O}_2 \longrightarrow 2 \mathrm{H}_2 \mathrm{O}+\mathrm{O}_2$
Volume strength of $30 \% \mathrm{H}_2 \mathrm{O}_2$ solution is 100 that means $1 \mathrm{~mL}$ of this solution on decomposition gives $100 \mathrm{~mL}$ oxygen.
$\begin{array}{lcc}\mathrm{SO}_2 & +\frac{1}{2} \mathrm{O}_2 \longrightarrow & \mathrm{SO}_3 \\ 1 \mathrm{~L} & \frac{1}{2} \mathrm{~L} & 1 \mathrm{~L} \\ 2 \mathrm{~L} & 1 \mathrm{~L} & 2 \mathrm{~L}\end{array}$
Since, $100 \mathrm{~mL}$ of oxygen is obtained by
$=1 \mathrm{~mL} \text { of } \mathrm{H}_2 \mathrm{O}_2$
$\therefore 1000 \mathrm{~mL}$ of oxygen will be obtained by
$\begin{aligned}
& =\frac{1}{100} \times 1000 \mathrm{~mL} \text { of } \mathrm{H}_2 \mathrm{O}_2 \\
& =10 \mathrm{~mL} \text { of } \mathrm{H}_2 \mathrm{O}_2
\end{aligned}$