Paragraph for Questions 15 and 16
X and Y are two volatile liquids with molar weights of 10gmol−1 and 40gmol−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=24cm, as shown. The tube is filled with an inert gas at 1 atmosphere pressure and a temperature of 300K. Vapours of X and Y react to form a product which is first observed at a distance dcm 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.
The experimental value of d is found to be smaller than the estimate obtained using Graham's law. This is due to