`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

Explanation

`"Given, "V_(A)=V_(B)=50"m L"`
`T_(B)=150s`
`T_(B)=200s`
`M_(B)=36`
`M_(A)=?`
From Graham's law of effusion
`(r_(B))/(r_(A))=sqrt((M_(A))/(M_(B)))=(V_(B)T_(A))/(T_(B)V_(A))`
`rArr" "sqrt((M_(A))/(36))=(V_(A)xx150)/(200xxV_(A))`
`"or "sqrt((M_(A))/(36))=(15)/(20)=(3)/(4)`
`(M_(A))/(36)=(9)/(16)`
`M_(A)=(9xx36)/(16)=(9xx9)/(4)=(81)/(4)=20.2`
`**` According to question, no option is correct in this condition, answer any option.
NOTE
If `T_(A)=200" s and "T_(B)=150s " then "M_(A)=64`