Which of the following is an example of a colligative property?

Boiling point elevation is indeed an example of a colligative property, which depends on the number of solute particles in a solution rather than the identity of the solute. Colligative properties are those properties that are affected by the ratio of solute to solvent particles in a solution, and boiling point elevation specifically occurs when a non-volatile solute is added to a solvent, resulting in an increase in the boiling point of the solution compared to the pure solvent.

The reason this occurs involves the interactions between solute and solvent molecules. The presence of solute particles disrupts the solvent's ability to escape into the gas phase (evaporate), thereby requiring a higher temperature to reach the boiling point. This effect is measurable and proportional to the concentration of the solute particles, which is characteristic of colligative properties.

In contrast, solubility refers to the ability of a solute to dissolve in a solvent and does not inherently involve the quantity of solute particles. The density of a solution is a physical property that defines how much mass is contained in a given volume and is influenced by many factors beyond just the number of solute particles. A color change in a reaction is related to chemical changes rather than the quantitative effects