Question

Cryoscopy is concerned with:
A) osmotic pressure of a solution
B) elevation of the boiling point of a solution
C) depression in freezing point of a solution
D) relative lowering in vapor pressure of a solution

Answer 1

Hint: Cryoscopy is a process related to determining the change in the physical properties in a solution after the addition of molecular substances. One needs to find out the particular change which it measures for particular physical property.

Complete step by step answer:
1) Cryoscopy can be defined as the concept which determines the lowered freezing points produced in liquid or solution by the number of dissolved substances in the liquid or solution. This method is used for the determination of the molecular weights of the solutes in the solution.

2) The concept of freezing-point depression can be applied to calculate the molar mass of the solute or the degree of dissociation of the solute present in the solution. This type of measurement is called the concept of cryoscopy.

3) The cryoscopy can be elaborated by its name in the Greek language as cryo stands for cold and scope stand for observing which makes it observe the cold. The cryoscopy concept depends on the exact measurement of the depression in the freezing point.

4) Hence, cryoscopy is used for the depression in the freezing point of a solution which shows option C as a correct choice.

And hence option C is a correct choice.

Note:
The depression in freezing-point can also be used as a tool for measurement of purity. The concept of freezing-point depression is the lowering of the freezing point of a large amount of solvent, on the addition of non-volatile solute substances. The depression in freezing-point is the reason that the seawater which has many salts in it remains liquid even after its temperature falls below zero degrees Celsius.