An open tank, 10 ft in diameter, containing benzene at 25 C is exposed to air.

An open tank, 10 ft in diameter, containing benzene at 25^οC is exposed to air. Above the liquid surface is a stagnant air film 0.2 in. thick. If the pressure is 1 atm and the air temperature is 25^οC, what is the loss of benzene in lb/day? The specific gravity of benzene at 60^οF is 0.877. The concentration of benzene outside the film is negligible. For benzene, the vapor pressure at 25^οC is 100 torr, and the diffusivity in air is 0.08 cm²/s.