, 8 larger mean free path for X as compared to that of Y.

, 12 larger mean free path for Y as compared to that of X.

and 16 increased collision frequency of Y with the inert gas as compared to that of X with the inert gas.

. Paragraph for Questions (i) & (ii) X and Y are two volatile liquids with molar weights of 10 g mol -1 and 40 g mol -1 respectively. Two cotton plugs, one soaked in X and the other soaked in Y, are simultaneously placed at the ends of a tube of length L = 24 cm, as shown in the figure. The tube is filled with an inert gas at 1 atmosphere pressure and a temperature of 300 K. Vapours of X and Y react to form a product which is first observed at a distance d cm from the plug soaked in X. Take X and Y to have equal molecular diameters and assume ideal behaviour for the inert gas and the two vapours. (i) The value of d in cm (shown in the figure), as estimated from Graham ’ s law, is 20 (ii) The experimental value of d is found to be smaller than the estimate obtained using Graham ’ s law. This is due to increased collision frequency of X with the inert gas as compared to that of Y with the inert gas.