Assuming that dry air contains `79% N_(2)" and "21% O_(2)` by volume, calculate the density of moist air at `25^(@)C` at one atmosphere when the relative humidity is 60%. The vapour pressure of water at `25^(@)C` is `23.76 mm" of "Hg`.

Options

A. `1.17 gL^(-1)`
B. `2.16 gL^(-1)`
C. `3.12 gL^(-1)`
D. `4.16 gL^(-1)`

Answer

A

Explanation

`P_("Total")= 760mm," "P_(H_2O)= 23.76(06)= 14.25mm`
`P_(N_2)= (745.744)(0.79)= 589.13mm," "P_(O_2)= (745.744)(0.21)= 156.6 mm`
`MW_("mix")= ((18)(14.256)+(589.1)28+(156.6)32)/(760)= 28.63 implies d= (PM)/(RT)= 1.17`.