Question

5 moles of liquid X and 10 moles of liquid Y make a solution having a vapor pressure of 70 torr. The vapor pressures of pure X and Y are 63 torr and 78 torr, respectively. Which of the following is true regarding the described solution?

• A. The solution shows negative deviation.
• B. The solution is ideal.
• C. The solution has volume greater than the sum of individual volumes.
• D. The solution shows positive deviation.

Hint:

A solution exhibits negative deviation when its vapor pressure is lower than expected based on Raoult's law. This occurs when the intermolecular forces between the components of the solution are stronger than between the components and the solvent.