A `4 : 1` molar mixture of `He` and `CH_(4)` is contained in a vessel at `20` bar pressure. Due to a hole in the vessel, the gas mixture leaks out. What is the composition of the mixture effusing out initially?

Explanation

Molar ration of He and `CH_(4)` is `4:1`
Partial pressure ration of He and `CH_(4) is 16 :4`
`( :'` total pressure =20 bar)
`(n_(He))/(n_(CH_(4))) = sqrt(M_(CH_(4))/(M_(He))) xx (P_(He))/(P_(CH_(4)))`
`( :'` time of diffusion for both is same)
`=sqrt((16)/(4))xx(16)/(4) =8:1`
The composition of mixture intially gone out for He and `CH_(4)` is `8:1` .