Problem $4.$

a$)$ Using the Pxy diagram, estimate the bubble$-$point pressure and the equilibrium vapor composition associated with a $40$ mole $\%$ benzene$-60$ mole$\%$ toluene liquid mixture at $100C.$

b$)$ If the mixture is steadily depressurized until the remaining liquid contains $25\%$ benzene, what is the final pressure and the equilibrium vapor composition?

$($Note: Label all steps on the figure$)$