Question

A hydrocarbon gas diffuses through a porous plug diffuses at the $1/6^{th}$ rate of diffusion of $H_2$ gas under similar conditions of $P$ and $T$. The gas is:

• A. $C_2{H}_6$
• B. $C_5{H}_{12}$
• C. $C_2{H}_2$
• D. $C_4{H}_{10}$

Answer 1

The correct option is B $C_5{H}_{12}$

As we know,
$r_1/r_2=\sqrt{M_2/M_1}$
$\frac{r_g}{r_{H_2}}=\frac{1}{6}=\sqrt{\frac{M_{H_2}}{M_g}}=\sqrt{\frac{2}{M_g}}$
$\therefore M_g=72$ so molar mass is 72
$\therefore$ Gas is $C_5{H}_{12}$.