Question

Sample of drinking water was found to be contaminated with chloroform chloroform is supposed to be careful janak in the level of contamination is found to be 15 ppm calculate mass percent of chloroform

Answer 1

Answer:(i) 15 ppm means 5 parts in million(106) parts.

∴ % by mass = 15/106 × 100 = 15×10-4 = 1.5×10-3 %

(ii) Molar mass of chloroform(CHCl3) = 12+1+(3×35.5) = 118.5 g mol-1

100g of the sample contain chloroform = 1.5×10-3g

∴ 1000 g(1 kg) of the sample will contain chloroform = 1.5×10-2 g

= 1.5×10-2/118.65 mole = 1.266×10-4 mole

∴ Molality = 1.266×10-4 m.

Explanation: