The density of a gas a is twice that of gas B. Molecular mass of A is half of the molecular of B. The ratio of the partial pressures of A and B is :

Options

A. `(1)/(4)`
B. `(1)/(4)`
C. `(4)/(1)`
D. `(2)/(1)`

Answer

C

Explanation

`"Density of a gas, d"=(pM)/(RT)`
`"or "p=(dRT)/(M)`
`therefore" "p_(A)=(d_(A)RT)/(M_(A)) and p_(B)=(d_(B)RT)/(M_(B))`
Given that : `d_(A)=2d_(B), M_(A)=(M_(B))/(2)`
`therefore" "p_(A)=(2d_(B)RT)/(M_(B)//2)=(4d_(B)RT)/(M_(B))`
`therefore" "(p_(A))/(p_(B))=(4d_(B)RT//M_(B))/(d_(B)RT//M_(B))=(4)/(1)`