QUestion $1$

The gas phase mass transfer coefficient for the evaporation of a drop of ethyl alcohol in a stream of air at $300K$ and $1\mathrm{.}2$ bar pressure is $k_G=2\mathrm{.}4{10}^{-6}$kmo$\frac{l}{s}.m^2.mmHg.$

a$)$ Calculate the values of the mass transfer coefficient if the deriving force is expressed in terms of difference in $($i$)$ mole fraction of alcohol in the gas phase and $($ii$)$ mole concentration of alcohol in kmo$\frac{l}{m^3}($iii$)$ mole concentration of alcohol in kmo$\frac{l}{m^3}$ for equimolar counter diffusion.

b$)$ Calculate the $F_G$

c$)$ If the diffusivity of alcohol in air is $0\mathrm{.}103c\frac{m^2}{s}$ at $300K,$ estimate the thickness of the stagnant gas file.

Vapor pressure of alcohol $=0\mathrm{.}0877$ bar at $300K.$