Question

Which of the following is not a colligative property?
A. Elevation in boiling point
B. Lowering of vapour pressure
C. Osmotic pressure
D. Freezing point

Answer 1

The colligative property depends on the effective nature of the interaction of the molecules. In a specific solution different molecules are involved and the level of the molecule differs based on the concentration of the solution, which is why the volume of the solvent as well as the level of solute mixed in it.

Complete answer:

A colligative property of a particular solution is defined as those properties which involve the ratio of the number of solute molecules and the solvent molecules. The interaction between these two molecules defines the colligative property for a particular solution as the number of molecules differs.
The colligative property is based on the interaction between the solute and the solvent together in the given solution. These interactions are very important for defining the colligative property of the solution in which the mixing of solvent and solute molecule takes place.
The elevation in boiling point and the reduction in freezing point of the specific solution depends on the type of solute which is present in the solution. If the solute changes in the solution, there can be a change in the freezing point and the boiling point of the solution.
The changing state occurs at a different temperature where the interaction between the molecule takes place. The lowering of vapour pressure is another factor associated with the molecular interaction of the solute and solvent. The osmotic pressure depends on the level of solute as compared to that of the solvent. This maintains a specific osmotic pressure in the given solution and based on the concentration of the solute the pressure changes. But even though the decrease in freezing point is a colligative property, the specific freezing point of the solution is not.

Therefore, the correct option is (D) Freezing point.

Note The colligative nature depends on molecular interaction between the molecules of different elements and their interactive properties. The interaction between the two molecules does not only mean bond formation but the weak interactions that take place due to the chemical nature of the components.