A sample of drinking water was found to be severely contaminated with chloroform $(CHCl_3$) supposed to be a carcinogen. The level of contamination was 15 ppm (by mass): determine the molality of chloroform in the water sample.

Question

$\begin{array}{1 1}1.25\times 10^{-4}m\\2.25\times 10^{-4}m\\3.25\times 10^{-4}m\\0.25\times 10^{-4}m\end{array} $