What is the density of wet air with 75% relative humidity at 1 atm and 300 K? Given : vapour pressure of `H_(2)O` is 30 torr and average molar mass of air is 29 g `mol^(_1)` .

Options

A. 1.614 g/L
B. 0.96 g/L
C. 1.06 g/L
D. 1.164 g/L

Answer

d

Explanation

(d) % Relative humidity
`=("Partial pressure of "H_(2)O)/("Vapour pressure of " H_(2)O)xx100`
`75=(P_(H_(2)O))/(30)xx100`
`P_(H_(2)O)=22.5"torr,"`
% of `H_(2)O` vapour in air
`=((22.5))/(760)xx100=2.96`
molar mass of wet air
`=(29xx97.04+2.96xx18)/(100)`
`=(2814.16+53.28)/(100)=28.67`
density of wet air `=(PM)/(RT)=(1xx28.67)/(0.0821xx300)`
`=1.164g//L`