Hint: We have four colligative properties of the solution: vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure.
Complete step by step answer:
In this question, we have asked which of the following options is an example of colligative property? Colligative properties are the properties of solutions that depend only on the ratio of the number of solute particles to the number of solvent molecules in a solution. It doesn't depend on the nature of the chemical species present. Basically, a solution has four colligative properties which are: •Relative lowering of vapor pressure
-Elevation of boiling point
-Depression of freezing point
-Our first option is the Freezing point. The freezing point is not a colligative property while the depression of freezing point on the addition of solute in a solvent is a colligative property. So, this option is wrong.
-Our next option is the boiling point. Again, the boiling point is not a colligative property, while an elevation in boiling point by the addition of solute in the solvent is a colligative property.
-Option C is vapor pressure. As we already described that we have only four colligative properties and vapor pressure is not one of them.
-Option D is osmotic pressure, which is one of the four colligative properties.
So, the correct option will be D. Osmotic pressure.
Note: The osmotic pressure of a solution is defined as the difference in pressure between the solution and the solvent when the two are in equilibrium across a semipermeable membrane (which allows the passage of solvent molecules but not of solute particles). If the two phases are at the same initial pressure, there is a net transfer of solvent across the membrane into the solution known as osmosis.