It is desired to recover hexane vapor from air using an absorption process. The absorption solvent is a nonvolatile mineral oil, which has a mass density of 0:80 g/cm³ and a molecular weight of 180 g/g mole. In the dilute concentration range, the equilibrium relationship for the dissolution of hexane vapor in the mineral oil is described by

P_A = 0.15 x_A where P_A has the units of atm.

Atthe present conditions of operation, the hexane partial pressure in the bulk gas stream is 0.015 atm, and the dissolved hexane in the bulk absorption solvent is 5.0 mol%. The total system pressure is 1.5 atm and the temperature is 20°C. The liquid film mass transfer coefficient, k_x, is 0:01 kg mol/m² s, and the gas film mass transfer coefficient, k_y, is 0:02 kg mol/m² s.

a. What is the overall mass-transfer coefficient based on the liquid phase, K_L?

b. What is the composition of hexane at the gas-liquid interface, in terms of p_{A; i} and x_{A; i}?