Final answer:
Higher concentrations of non-volatile solutes make it harder for the solvent to evaporate, leading to lower vapor pressure and an increased boiling point of the solution.
Step-by-step explanation:
Because of solute-solvent intermolecular attraction, higher concentrations of non-volatile solutes make it harder for the solvent to escape to the vapor phase. When a nonvolatile solute is added to a solvent, it occupies space at the surface, preventing solvent molecules from easily evaporating. This results in a lower vapor pressure of the solution compared to the pure solvent. In other words, the presence of a nonvolatile solute impedes the solvent's molecules from entering the gaseous phase, which consequently increases the boiling point of the solution, a phenomenon known as boiling point elevation.