`50 mL` of each gas `A` and of gas `B` takes `150 and 200` seconds respectively for effusing through a pin hole under the similar conditon. If molecular mass of gas `B` is `36`, then the molecular mass of gas `A` will be

Options

A. `96`
B. `128`
C. `32`
D. `64`

Answer

C

Explanation

`(V_(A))/(t_(B))//(VB)/(t_(B))=sqrt((M_(B))/(M_(A)))`
`implies (200)/(150)=sqrt((36)/(M_(A)))implies(4)/(3)=sqrt((36)/(M_(A)))`
`implies(16)/(9)=(36)/(M_(A))implies M_(A)=(81)/(4)=20.25`
So, most approximate answer is `32`.