Question: In a binary solution of A and B, if the vapor pressure of pure A is 150 mmHg and pure B is 50 mmHg, what is the total vapor pressure when the mole fraction of A is 0.4?
Options:
Correct Answer: 120 mmHg
Solution:
Total vapor pressure = (X_A * P_A^0) + (X_B * P_B^0) = (0.4 * 150) + (0.6 * 50) = 60 + 30 = 90 mmHg.