2. Consider a diffusion of A through a hypothetical isothermalonisothermal spherical stagnant gas B film surrounding a droplet of liquid A. The temperature (T) within the gas film varies with radial distance as rn. The diffusivity of A in B varies as T1.5. a) State your assumptions and derive governing equation along with BCs for diffusion of A through a spherical shell of gas B. b) Establish the concentration profile of A in B in terms of mole fraction of A. c) Determine molar flow of A across any spherical surface of radius r between R1 and R2 d) Determine the concentration profile and molar flow rate of A for an isothermal film. e) Obtain the expression for concentration profile and molar flow rate of A for n=2