Pure water at a velocity of 0.11 m/s is flowing at 26.1C past a flat plate of solid benzoic acid where L= 0.4 m. ( DAB= 1.245 x10-9 m2/s, viscosity= 8.71 x10-9 Pa.s, density= 996 kg/ m3 .

a) Assuming dilute solutions, calculate the mass transfer coefficient

b) Using film model, calculate the equivalent film thickness

c) Calculate time of penetration by using penetration theory