Q. Hydrogen diffuses six times faster than gas $A.$ The molar mass of gas $A$ is
A) 72
B) 6
C) 24
D) 36
Explanation
(a)
Given, $\frac{r_{H_{2}}}{r_{A}} = 6,\ M_{H_{2}} = 2,\ M_{A} = ?$
From Graham’s law of diffusion,
$\frac{r_{H_{2}}}{r_{A}} = \sqrt{\frac{M_{A}}{M_{H_{2}}}}$
$or\ \ \ 6 = \sqrt{\frac{M_{A}}{2}}\ or\ \ 36 = \frac{M_{A}}{2}$
$\therefore\ \ M_{A} = 72$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.