A sample of drinking water was found to be severely contaminated with chloroform, CHCl3, supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass). (i) Express this in per cent by mass. (ii) Determine the molality of chloroform in the water sample.

Home » A sample of drinking water was found to be severely contaminated with chloroform, CHCl3, supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass). (i) Express this in per cent by mass. (ii) Determine the molality of chloroform in the water sample.

CBSE | Chemistry | Class 11 | NCERT | Some Basic Concepts of Chemistry

A sample of drinking water was found to be severely contaminated with chloroform, CHCl3, supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass). (i) Express this in per cent by mass. (ii) Determine the molality of chloroform in the water sample.

(a) $1 ppm = 1 part out of 1 million parts.$

Mass percent of 15 ppm chloroform in H₂O= $\frac{15}{{{10}^{6}}}\times 100$ $\approx 1.5 \times{10}^{-3}%$

$(b)$ 100 grams of the sample is having 1.5 × g of

$\text{1000 grams of the sample is having 1}\text{.5 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{-2}}}\text{g of }\!\!~\!\!\text{ CHC}{{\text{l}}_{\text{3}}}$