Final answer:
In a solution, when a solute is added to a pure solvent, the freezing point decreases and the boiling point increases due to the solute-solvent interactions.
Step-by-step explanation:
In a solution, when a solute is added to a pure solvent, the freezing point decreases and the boiling point increases.
When a solute is added to a solvent, the solute-solvent interactions disrupt the solvent's ability to form a solid, resulting in a lower freezing point. This is known as freezing point depression. For example, when salt is used on icy roads, the freezing point of water is lowered, preventing it from freezing at its normal 0°C.
The boiling point of a solution is higher than the boiling point of a pure solvent. This is because the presence of solute particles in the solution increases its boiling point. The solute particles interfere with the escape of solvent molecules into the gas phase, requiring a higher temperature for the solution to reach its boiling point.