Some amount of dichloromethane $\left(\mathrm{CH}_{2} \mathrm{Cl}_{2}\right)$ is added to $671.141 \mathrm{~mL}$ of chloroform $\left(\mathrm{CHCl}_{3}\right)$ to prepare $2.6 \times 10^{-3} \mathrm{M}$ solution of $\mathrm{CH}_{2} \mathrm{Cl}_{2}(\mathrm{DCM})$. The concentration of $\mathrm{DCM}$ is ___________ ppm (by mass).
Given :
atomic mass : C = 12
H = 1
Cl = 35.5
density of $\mathrm{CHCl}_{3}=1.49 \mathrm{~g} \mathrm{~cm}^{-3}$
Answer (integer)
148
Solution
<p>Mass of $\mathrm{CHCl_3=671.141\times1.49=1000}$ gm</p>
<p>$2.6 \times {10^{ - 3}} = {{moles\,of\,C{H_2}C{l_2}} \over {0.671141}}$</p>
<p>$\Rightarrow$ moles of $C{H_2}C{l_2} = 1.74496 \times {10^{ - 3}}$</p>
<p>mass of $C{H_2}C{l_2} = 148.32 \times {10^{ - 3}}$ gm</p>
<p>Composition of $C{H_2}C{l_2} = {{148.32 \times {{10}^{ - 3}}} \over {1000}} \times {10^6}$</p>
<p>= 148.32 ppm</p>
<p>$\approx$ 148</p>
About this question
Subject: Chemistry · Chapter: Some Basic Concepts of Chemistry · Topic: Mole Concept
This question is part of PrepWiser's free JEE Main question bank. 163 more solved questions on Some Basic Concepts of Chemistry are available — start with the harder ones if your accuracy is >70%.