Question

What will be the molality of chloroform in the water sample which contains $15\, ppm$ chloroform by mass?

• A. $1.25\times10^{-4}m$
• B. $2.5\times10^{-4}m$
• C. $1.5\times10^{-3}m$
• D. $1.25\times10^{-5}m$

Answer 1

Answer: (A)

$15\, ppm = \frac{15}{10^{6}} \times 10^{2} = 1.5 \times 10^{-3}\, g$
Molality of $CHCl_{3}$ solution $= \frac{1.5\times10^{-3}}{100} \times \frac{1000}{119.5}$
$=1.25\times10^{-4}\,m$