When `2g` of gas `A` is introduced into an evacuated flask kept at `25^(@)C` the pressure is found to be `1atm`. If `3g` of another gas `B` is then added to the same flask the total pressure becomes `1.5 atm` .Find the ratio of molar mass of `A` to molar mass of `B` .

Options

A. `1:3`
B. `3:1`
C. `2:3`
D. `3:2`

Answer

A

Explanation

`P propto n`
`n_1 = (2)/(m_1) P_(1)/P_(2) = (n_(1))/(n_(2) + n_(1))`
`n_(2) = (3)/m_(2) n_(2)+n_(1) = 1.5 n_(1)`
` n_(2) = (n_(1))/(2)`
` (3)/m_(2) =(2)/(m_(1)xx2)`
`m_(1)/m_(2) =(1)/(3)`