Question

1-propanol (P1° = 20.9 Torr at 25 °C) and 2-propanol (P2° = 45.2 Torr at 25 °C) form ideal solutions in all proportions. Let x1 and x2 represent the mole fractions of 1-propanol and 2-propanol in a liquid mixture, respectively, and y1 and y2 represent the mole fractions of each in the vapor phase. For a solution of these liquids with x1 = 0.200, calculate the composition of the vapor phase at 25 °C.

y1=? Y2=?

Answer 1

Can you do P1soln = X1*P1
P2soln = X2*P2
Total pressure of soln = P1soln + P2soln.

Then composition.
y1 = P1soln/total P
y2 = P2soln/total P