An open circular tank of 0.25 m diameter contains Benzene at 28C. It is exposed to atmosphere In such a manner that the liquid is covered by a stagnant air film of 2.0 cm high. The concentration of Benzene beyond air film may be assumed negligible. The following data may be assumed: Vapor pressure of Benzene at 28C = 100 mm Hg. DBenzene-Air = 0.09 cm/s. PBenzene -880 kg / m. If the cost of Benzene is Rs. 20/L, find the loss incurred per year. (12) (April '99). At 0C, diffusivity DAB = 6.12 x 105 m /s. What is the value of diffusivity DAB at 100 C? A and B are gaseous molecules. (2) (Nov/Dec '07)