Question

question 11
why is the vapor pressure of a solution lower than the vapor pressure of the pure solvent?
a because colloidal dispersion interferes with surface tension
b because fewer solvent molecules are present on the surface
c because the particles on the surface have less energy
d because increased intermolecular forces prevent solvent molecules from evaporating

Explanation:

In a solution, solute particles occupy some surface - area. This reduces the number of solvent molecules at the surface available for evaporation. Vapor pressure is related to the number of solvent molecules evaporating. Fewer solvent molecules at the surface lead to lower vapor pressure compared to pure solvent.

Answer:

B. because fewer solvent molecules are present on the surface