Two separate bulbs contain gas A and gas B. the density of gas A is twice as that of B. the molecular mass of A is half as that of B. if temperature is constant, the ratio of the pressure of A and B is-

Options

A. `1:1`
B. `1:2`
C. `4:1`
D. `2:1`

Answer

C

Explanation

`d=(PM)/(RT)`
Given, `(d_(A))/(d_(B))=2,(M_(A))/(M_(B))=(1)/(2)`
`d_(A)/d_(B)=(P_(A)M_(A))/(RT) xx(RT)/(P_(B)M_(B))=2`
or, `(P_(A))/(P_B)xx(M_(A))/(M_(B))=2`
or, `(P_(A))/(P_(B))xx(1)/(2)=2`
or, `(P_(A))/(P_(B))=4:1`.