Benzene is stored in an open rectangular tank with the dimensions of 5 m length, 7 m width and 10 m height. A 15 mm stagnant air film is covering the benzene surface beyond which benzene is absent. At the atmospheric temperature of 25 C, its corresponding vapour pressure is 150 mm Hg, calculate the rate loss of the benzene in kmol/s. Given the diffusivity of benzene is 0.02 m2 /h and total pressure is 1.0 atm.