Question

The strengths of $5.6$ volume hydrogen peroxide (of density $1 \,g / mL )$ in terms of mass percentage and molarity (M), respectively, are:
(Take molar mass of hydrogen peroxide as $34 \,g / mol )$

• A. $1.7$ and $0.25$
• B. $1.7$ and $0.5$
• C. $0.85$ and $0.5$
• D. $0.85$ and $0.25$

Answer 1

Answer: (B)

Volume strength $=11.2 \times$ molarity

$\Rightarrow $ molarity $=\frac{5.6}{11.2}=0.5$

Assuming 1 litre solution;

mass of solution $=1000 ml \times 1 g / ml =1000\, g$

mass of solute = moles $\times$ molar mass

$=0.5\,mol \times 34\,g /mol$

$=17\,gm$

$\Rightarrow $ mass $\%=\frac{17}{1000} \times 100=1.7 \%$