Question

How do we know that the freezing point depression is a colligative property?

Answer 1

First of all we should be aware of the freezing point depression and also about the colligative property. The decrease of the freezing point of a solvent during the addition of a non-volatile solute, is generally termed as the freezing point depression

Complete step-by-step answer:
The properties which mainly depend on the concentration of solute molecules or ions, and are independent of the identity of the solute are generally termed as Colligative properties. These properties generally include boiling point elevation, vapor pressure lowering, osmotic pressure and freezing point depression.

Since, the freezing point depression is generally a part of colligative property. It is generally observed in the solution which is the result of the formation of solute particles from the solvent molecules. The freezing point of a pure solvent is higher than that of a solution, and it is directly proportional to the solute’s molarity.

Freezing point depression is the phenomenon which generally describes the reason why the freezing point of a solute generally decreases after the adding of a solute in the solvent. The examples of the freezing point are – alcohol in water, salt in water, etc. The freezing point depression can also be explained in the terms of vapor pressure.

Difference between freezing point and freezing point depression: The freezing point is the temperature in which a liquid changes into solid while freezing point depression describes the reason for lowering the freezing point of a solvent, while adding a solvent in it.

Note: The colligative properties are important as they are used in many natural phenomena and also in technological applications. There are many advantages of using the principle of depression in freezing point. Such as:- The most common automobile antifreeze is Ethylene Glycol as it is non-volatile and soluble in water, thus used as coolant in automobile radiators.