The density of gas `A` is twice that of B at the same temperature the molecular weight of gas B is twice that of A. The ratio of pressure of gas A and B will be :

Options

A. `1 : 6`
B. `1:1`
C. `4 : 1`
D. `1 : 4`

Answer

C

Explanation

`d_(A) = 2 d_(B) , 2 M_(A) = M_(B) `,
`because PM = d RT `
`therefore (P_(A))/(P_(B)) xx (M_(A))/(M_(B)) = (d_(A))/(d_(B)) xx (RT)/(RT)`
`implies (P_(A))/(P_(B)) xx (1)/(2) = 2 `
`(P_(A))/(P_(B)) = (4)/(1)`