Pure aniline is evaporating through a stagnant air film of 1 mm thickness at 300 K and a total pressure of 100 KPa. The vapor pressure of aniline at 300 K is 0.1 KPa. The total molar concentration under these conditions is 40.1 mole/m3. The diffusivity of aniline in air is 0.74 × 10-5m2/s. The numerical value of mass transfer co-efficient is 7.4 × 10-3. Its units are_______________________?

Question

Accepted Answer

mole/m2.s.Pa. The mass transfer coefficient (k_c) has units of molar flux per concentration difference. Given the options, mole/m^2.s.Pa is dimensionally consistent with mass transfer coefficients derived from partial pressure driving forces.