The rate of diffusion of methane is twice that of `X` . The molecular mass of `X` is

Options

A. `16`
B. `32`
C. `80`
D. `64`

Answer

D

Explanation

According to Graham's law of diffusion , we have
`(r_(CH_(4)))/(r_(X)) = sqrt((M_(X))/(M_(CH_(4))))`
Since `r_(CH_(4)) = 2r_(X)` , we have
`(r_(CH_(4)))/(r_(X)) = sqrt((M_(X))/(16))`
`(2)^(2) = (M_(X))/(16)`
or `M_(X) = 4 xx 16 = 64 g mol^(-1)`
Thus , the molecular mass of `X is 64 amu`.