At identical temperature and pressure the rate of diffusion of hydrogen gas is `3sqrt3` 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. 6
D. 8

Answer

B

Explanation

`(r_(1))/(r_(2)) = sqrt((M_(2))/(M_(1))) , (r_(1))/(r_("hydrogen")) = 3 sqrt3 : M_(1) = 2`
`:. 3 sqrt3 = sqrt((M_(2))/(2)) " or " (M_(2))/(2) = 9 xx 3 = 27`
`:. M_(2) = 54`
Now `12 xx n + 2n - 2 = 56`
`14 n = 56 " or " n = 4`