Question

How many '$mL$' of perhydrol is required to produce sufficient oxygen which can be used to completely convert $2L$ of $S{O}_2$ gas to $S{O}_3$ gas?

• A. 10 mL
• B. 5 mL
• C. 20 mL
• D. 30 mL

Answer 1

Answer: (A)

Perhydrol means $30\%$ solution of $H_2{O}_2$.
$H_2{O}_2$ decomposes as
$2H_2{O}_2\to 2H_{2}O+O_2$
Volume strength of $30\%H_2{O}_2$ solution is $100$ that means $1mL$ of this solution on decomposition gives $100mL$ oxygen.

Since, $100mL$ of oxygen is obtained by $=1mL$ of $H_2{O}_2$
$\therefore 1000mL$ of oxygen will be obtained by
$=\frac{1}{100}\times 1000mL$ of $H_2{O}_2$
$=10mL$ of $H_2{O}_2$