Question

A sample of $H_2{O}_2$ solution labelled as $28$ volume has density of $265$ g/L. Mark the correct option(s) representing concentration of same solution in other units.

• A. Molarity of $H_2{O}_2=2.5$
• B. Percentage $w/v=17$
• C. Mole fraction of $H_2{O}_2=0.2$
• D. Molality of $H_2{O}_2=13.88$

Answer 1

Answer: (A), (C), (D)

The correct options are
A Molarity of $H_2{O}_2=2.5$
C Mole fraction of $H_2{O}_2=0.2$
D Molality of $H_2{O}_2=13.88$

Volume strength is $28$. Molarity is $\frac{\text{volume strength}}{11.2}=\frac{28}{11.2}=2.5$.

Percentage w/v is $\frac{\text{volume strength}\times 68}{22.4}=\frac{28\times 68}{224}=8.5$.

$1$ L of solution contains $2.5$ moles of hydrogen peroxide.

Number of moles of water $=\frac{265g/L\times 1L-2.5mol\times 34g/mol}{18}=10$ moles

Mole fraction of hydrogen peroxide $=\frac{2.5}{10+2.5}=0.2$

Molality $=\frac{2.5}{0.180}=13.88$

Thus options A, C and D are correct.