Kaplan Nursing Entrance Exam Practice 2026 – Comprehensive Prep

When antifreeze is added to water in a car's radiator, the boiling point of the resulting solution increases. This phenomenon is known as boiling point elevation, which occurs because the addition of a solute (in this case, antifreeze) to a solvent (water) disrupts the solvent's ability to vaporize.

In a pure solvent, molecules have a certain energy threshold to escape into the vapor phase, which corresponds to the boiling point. However, when a solute is introduced, it interferes with the solvent molecules, requiring a higher temperature to provide enough energy for the solvent molecules to escape into the vapor phase effectively.

This property is particularly important in automotive cooling systems. The elevated boiling point helps to prevent the coolant from boiling over, allowing the radiator to operate effectively in high-temperature conditions. This ensures optimal engine performance and protects the engine from overheating. Thus, the correct answer reflects the scientific principle of boiling point elevation due to the addition of a solute such as antifreeze to water.