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

Answer

B

Explanation

`(r_(1))/(r_(2))=sqrt((M_(w_(2)))/(M_(w_(1))))`
`(V_(1))/(t_(1))xx(t_(2))/(V_(2))=sqrt((M_(w_(2)))/(M_(w_(1))))`
`(50)/(150)xx(200)/(50)=sqrt((36)/(M_(w_(1))))`
`(4)/(3)=sqrt((36)/(M_(w_(1))))`
`(16)/(9)=(36)/(M_(w_(1)))`
`M_(w_(1))=(36xx9)/(16)=20.25`