Alcohol vapour is diffusing through a layer of water vapour under equimolar counter diffusion at 35°C and 1 atm. pressure. The molal concentration of alcohol on the two sides of the gas film (water vapour) 0.3 mm thick are 80% and 10% respectively. Assuming the diffusivity of alcohol-water vapour to be 0.18 cm²/s, (i) calculate the rate of diffusion of alcohol and water vapour in kg/hr through an area of 100 cm² (ii) if the water vapour layer is stagnant, estimate the rate of diffusion of alcohol vapour.