NCERT Class XII Chemistry
Chapter - Solutions
Questions with Solutions
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Question : 9
Total: 53
A sample of drinking water was found to be severely contaminated with chloroform,CHCl 3
(i) Express this in percent by mass.
(ii) Determine the molality of chloroform in the water sample.
(i) Express this in percent by mass.
(ii) Determine the molality of chloroform in the water sample.
Solution:
(i) 15 ppm means 15 parts in million (10 6
% =
× 100 = 1.5 × 10 − 3
(ii) Mass of solvent= 10 6 g
Molar mass ofCHCl 3 = 12 + 1 + 3 × 35.5 = 119.5 g mol − 1
No. of moles of CHCl 3 =
=
∴ =
× 1000 = 1.25 × 10 − 4 m
(ii) Mass of solvent
Molar mass of
No. of moles of
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