NCERT Class XII Chemistry
Chapter - Solutions
Questions with Solutions
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Question : 39
Total: 53
The air is a mixture of a number of gases. The major components are oxygen and nitrogen with approximate proportion of 20% and 79% by volume at 298 K. The water is in equilibrium with air at a pressure of 10 atm. At 298 K, if the Henry’s law constantsfor oxygen and nitrogen are 3.30 × 10 7 6.51 × 10 7
Solution:
Total pressure of air in equilibrium with water = 10 atmosphere
As air contains 20% oxygen and 79% nitrogen by volume,
Partial pressure of oxygen( p O 2 ) =
× 10
= 2 atm = 2 × 760 mm Hg = 1520 mm Hg
Partial pressure of nitrogen( p N 2 ) =
× 10
= 7.9 atm = 7.9 × 760 mm Hg = 6004 mm Hg
K H ( O 2 ) = 3.30 × 10 7 K H ( N 2 ) = 6.51 × 10 7
Applying Henry’s law ,p O 2 = K H × x O 2
or,x O 2 =
=
= 4.61 × 10 − 5
p N 2 = K H × x N 2
x N 2 =
=
= 9.22 × 10 − 5
As air contains 20% oxygen and 79% nitrogen by volume,
Partial pressure of oxygen
= 2 atm = 2 × 760 mm Hg = 1520 mm Hg
Partial pressure of nitrogen
= 7.9 atm = 7.9 × 760 mm Hg = 6004 mm Hg
Applying Henry’s law ,
or,
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