At `0^(@)C`, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide ?

Explanation

Relation between density pressure and molecular mass according to eq. `M=(dRT)/(p)`
`d=(pM)/(RT)`
`therefore M=(dRT)/(p)`
where, T = 0.2
R = gas constant
d = density
Thus, dRT = Constant No. (K)
`therefore M =(K)/(p)` and `M prop (1)/(p)`
Thus, `M_(1)p_(1)=M_(2)p_(2)`
where, `M_(1)=` molecular mass of oxide = (?)
`M_(2)=` molecular mass of `N_(2)=28 g mol^(-1)`
`p_(1)=` pressure of oxide = 2 bar
`p_(2)=` pressure of `N_(2)=5` bar
Thus, `M_(1)xx2` bar `= 28xx5`
`therefore M_(1)=(28xx5)/(2)=70 g mol^(-1)`