Q3(a) The diffusivity of Carbon tetrachloride (CCI) in oxygen is determined by evaporating it into a stream of oxygen at 273 K and 100 kPa. The cross sectional area of the tube is 8.2x105 m2 and the liquid level in the tube is maintained at 200 mm from the top of the tube. The vapour pressure of carbon tetrachloride at 273 K is 4.4 kPa. It has been observed that 2.18x10 m of carbon tetrachloride is evaporated in 10 hours after attaining steady state. Determine the diffusivity of carbon tetrachloride in air at 273 K. Density of the liquid is 1540 kg/m?. Molar Mass of chlorine is 35 kg/mole. (b) Explain Stefan's method of diffusion with a neat sketch. [12] [8]