Q1. Mass Transfer coefficient relationships The gas-phase mass transfer coefficient for the evaporation of a drop of ethyl alcohol in a stream of air at 300 K and 1.2 bar pressure

is kg = 2.4 x 10-6 kmol/(s.m² (mm Hg)). Calculate values of mass transfer coefficient if the driving force is expressed in terms of difference in: (i) mole fraction of alcohol in the gas phase; (ii) mole fraction of alcohol; (iii) concentration of alcohol in kmol/m³. If the diffusivity of alcohol in air is 0.102 cm²/s at 1 atm and 0 C, estimate the thickness of the gas film. Vapor pressure of alcohol = 0.0877 bar at 300 K.