At identical temperature and pressure, the rate of diffusion of hydrogen gas is `3sqrt(3)` times that of a hydrocarbon having molecular formula `C_(n)H_(2n-n)`. What is the value of n?

Options

A. 1
B. 4
C. 3
D. 8

Answer

B

Explanation

`r_1 prop (1)/(sqrtM_1) or r_1/r_2 = sqrt(M_2/M_1)`
Given r_1 = 3sqrt(3r_2) rArr r_1/r_2 = sqrt(M_2/M_1) = 3sqrt3`
`3 sqrt3 = sqrt((M_2)/(2))`
`therefore 27 = (M_2)/(2)`
`M_2 = 27 xx 2 = 54`
Now `12 xx n + 2n - 2 = 54`
14n = 56 rArr n = 4` .