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What are the factors on which the colligative properties of a solution depends?

Last updated date: 20th Jul 2024
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Hint: Colligative properties are basically the properties of solutions and these properties depend upon the proportion of number of particles of solute and number of particles of solvent present in the solution.

Complete answer:
Here, we need to explain the factors on which these colligative properties depend. Colligative properties are just the physical changes that occur due to the addition of solute into a solvent. These properties depend upon the amount of solute particles added or present into the solvent but they are not dependent upon the solute particle’s type but is dependent upon the type of the solvent particles.
Colligative properties involve:
Relative lowering of vapor pressure or Raoult’s law
Elevation of boiling point
Depression of freezing point
Osmotic pressure
Relative lowering of vapor pressure: Raoult’s law tells us about the relationship between the vapor pressure of the components of the solution and the component’s concentration. The partial pressure which is applied by any of the components of that ideal solution is equal to the products of vapor pressure of its pure component and the mole fraction.
Mathematically, \[\]${P_A} = X{ _A}P{^\circ _A}$
Where ${P_A}$ stand for the partial pressure due to component A. ${X_A}$ stands for the mole fraction of component A and $P{^\circ _A}$ stands for the vapour pressure due to the pure form of component A.
Elevation of boiling point: After the addition of non-volatile solute into a solvent an increase in the boiling point of the solution was observed and that increase in boiling point is denoted as $\Delta {T_b}$. Boiling point elevation is equal to the molal concentration of the solute particles.
$\Delta {T_b} = {K_b}m$ ,where ${K_b}$ stands for the boiling point elevation constant.
Depression in freezing point: Freezing point depression is denoted as $\Delta {T_f}$. In a diluted solution, there is a decrease in the freezing point when it is compared to its pure solvent. Freezing point depression is equal to the molal concentration of solute particles.
$\Delta {T_f} = {K_f}m$, where ${K_f}$ stands for the freezing point depression constant.
Osmotic Pressure: Osmosis is a phenomenon in which solvent molecules flow across a semipermeable membrane from the diluted side to its concentrated side.
Osmotic pressure of a solution can be defined as the pressure which is required to stop this flow from one side to the other across the semipermeable membrane.
$\pi = CRT$, where R stands for the gas constant.

This concept of colligative properties is totally different from the physical properties, so do not mix them up. Colligative properties depend upon the amount of the solute particles present whereas physical properties depend upon their nature, that is, of solute as well as solvent.