What is the effect of colligative properties on vapor pressure?

Colligative properties, which depend on the number of solute particles in a solution, have a significant effect on the vapor pressure of a solvent. When a non-volatile solute is added to a solvent, the vapor pressure of that solvent decreases. This occurs because the presence of solute particles disrupts the ability of solvent molecules to escape into the vapor phase. As a result, fewer solvent molecules are able to enter the vapor phase from the liquid phase, leading to a lowered vapor pressure.

This principle is particularly evident with solutions, where the addition of solute reduces the overall concentration of solvent molecules at the surface of the liquid, effectively making it harder for those molecules to transition into the gas phase. Consequently, the presence of a solute in a solvent results in a reduction of vapor pressure compared to the pure solvent.