Q. $NH_{3}\ and\ HCl$ gas are introduced simultaneously from the two ends of a long tube. A white ring of $NH_{4}Cl$ appears first
A) Nearer to the HCl end
B) At the centre of the tube
C) Throughout the tube
D) Nearer to the $NH_{3}$ end
Explanation
(a)
White ring of ${NH}_{4}Cl$ will appear nearer to the HCl end. The reason is that HCl (mol. wt. = 36.5) is heavier than ${NH}_{3}$ (mol. wt. Hence, according to Graham’s law of diffusion, the rate of diffusion of ${NH}_{3}$ will be higher than that of HCl.)
$\frac{r_{1}}{r_{2}} = \sqrt{\frac{M_{2}}{M_{1}}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.