Question

The experimental value of $d$ is found to be smaller than the estimate obtained using Graham's law. This is due to
(1) larger mean free path for A as a compared of that of Y
(2) larger mean free path for Y as compared to that of A
(3) increased collision frequency of Y with the inert gas as compared to that of A with the inert gas
(4) increased collision frequency of A with the inert gas as compared to that of Y with the inert gas

• A. larger mean free path for A as a compared of that of Y
• B. larger mean free path for Y as compared to that of A
• C. increased collision frequency of Y with the inert gas as compared to that of A with the inert gas
• D. increased collision frequency of A with the inert gas as compared to that of Y with the inert gas

Answer 1

Answer: (D)

$x$ is a lighter gas thany, hencex has greater molecular speed. Due to greater molecular speed of $x$, it will have smaller mean free path and greater collision frequency with the inert gas molecules. As a result .v will take more time to travel a given distance along a straight line. Hence $x$ and $y$ will meet at a distance smaller than one calculated from Graham's law.