Question

How many ' $mL$' of perhydrol is required to produce sufficient oxygen which can be used to completely convert $2 \,L$ of $SO _{2}$ gas to $SO _{3}$ gas?

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

Answer 1

Answer: (A)

10 mL

Answer 2

Perhydrol means $30 \%$ solution of $H _{2} O _{2}$. $H _{2} O _{2}$ decomposes as
$2 H _{2} O _{2} \longrightarrow 2 H _{2} O + O _{2}$
Volume strength of $30 \% H _{2} O _{2}$ solution is $100$ that means $1\, mL$ of this solution on decomposition gives $100\, mL$ oxygen.

Since, $100\, mL$ of oxygen is obtained by
$=1\, mL$ of $H _{2} O _{2}$
$\therefore 1000 \,mL$ of oxygen will be obtained by
$=\frac{1}{100} \times 1000\, mL$ of $H _{2} O _{2}$
$=10\, mL$ of $H _{2} O _{2}$