Question:
The strengths of $5.6$ volume hydrogen peroxide (of density $1 \mathrm{~g} / \mathrm{mL}$ ) in terms of mass percentage and molarity (M), respectively, are:
(Take molar mass of hydrogen peroxide as $34 \mathrm{~g} / \mathrm{mol}$ )
Correct Option: , 2
Solution:
Volume strength $=11.2 \times$ molarity
$\Rightarrow$ molarity $=\frac{5.6}{11.2}=0.5$
Assuming 1 litre solution;
mass of solution $=1000 \mathrm{ml} \times 1 \mathrm{~g} / \mathrm{ml}=1000 \mathrm{~g}$
mass of solute $=$ moles $\times$ molar mass
$=0.5 \mathrm{~mol} \times 34 \mathrm{~g} / \mathrm{mol}$
$=17 \mathrm{gm} .$
$\Rightarrow \operatorname{mass} \%=\frac{17}{1000} \times 100=1.7 \%$