Air contains 79% N2 and 21% O2 by volume. If the barometric pressure is 750mmHg the partial pressure of oxygen is: (dN2=1.25,dO2=1.42g/m)
A
157.5mm of Hg
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B
175.5mm of Hg
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C
315.0mm of Hg
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D
None
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Solution
The correct option is B157.5mm of Hg
You can easily calculate the partial pressure of oxygen keeping in mind the definition of partial pressure.
First of all You have the find out the mole fraction of the oxygen and we know that mole fraction can be calculated from percentage composition of the gas divided by the total percentage of all gases
So here oxygen is 21% = mole fraction of 21 % oxygen =21100=0.21
Here total pressure is give which is =750 mm of Hg
Partial pressure of oxygen will be =750×0.21=157.5mmofHg.