Problem 12.28: Use the UNIFAC equation to do the following calculations for the system methanol(1)- acetic acid(2):

a) Calculate the bubble pressure of a solution that contains 80% (by mole) methanol at 80 °C.

b) Do you expect the volume of the system to expand or to contract upon mixing the pure components?

c) Calculate the fugacity of methanol in solution with acetic acid at xMeOH = 0.8, 80 °C, 0.4 bar.

d) Repeat the previous calculation at the bubble pressure of the solution instead of 0.4 bar.

e) Calculate the chemical potential of methanol in solution with acetic acid at xMeOH = 0.8, 80 °C, 0.4 bar. The reference state is the pure liquid at 80 °C, 0.4 bar.

f) Repeat the previous part if the reference state is the pure liquid at saturation at 80 °C.

Additional data: The saturation pressures of methanol and acetic acid at 80 °C are 1.81 and 0.2763 bar, respectively.