Question

Some amount of dichloromethane $\left( CH _2 Cl _2\right)$ is added to $671.141 \,mL$ of chloroform $\left( CHCl _3\right)$ to prepare $2.6 \times 10^{-3} M$ solution of $CH _2 Cl _2$ (DCM) The concentration of DCM is ______$ppm$ (by mass) Given: atomic mass : $C =12$ $H =1$ $Cl =35.5$ density of $CHCl _3=1.49\, g \,cm ^{-3}$

Answer 1

The correct answer is 148ppm
$Molarity = \frac{mole}{volume} ​$
$2.6×10^{−3}=\frac{x/85}{0.67141}$
$x=0.148g$
conc. Fo DCM in ppm
$=\frac{0.148}{1.49×671.141}×10^6$
=148ppm