Define colligative properties.

• A. Properties that depend on the number of solute particles
• B. Properties that depend on the identity of solute particles
• C. Properties that depend on solvent color
• D. Properties that depend on solvent viscosity

Answer: (A)

Colligative properties are properties that depend on the number of solute particles in a solution, not on what those particles are. This means that adding more solute particles changes properties like boiling point, freezing point, vapor pressure, and osmotic pressure regardless of the solute’s identity. Examples include boiling point elevation, freezing point depression, and vapor pressure lowering, all tied to how many particles are present rather than their specific chemical nature. The correct statement captures this dependence on particle count, which is why it best defines colligative properties. The identity, color, or viscosity of the solute don’t determine these properties in the same way, though those factors can affect other, non-colligative behaviors.