Question

Explain how the concentration of a solute in a solution influences its boiling point and freezing point.

Answer 1

Explanation:

Elevation of boiling point :

$\Delta T_b=K_b\times molality$

$\Delta T=K_b\times \frac{\text{mass of solute}}{\text{Molar mass of solute}\times \text{Weight of solvent}}$

From the above expression we can say that :

$\Delta T_b\propto {\text{mass of solute}$

Increasing the mass of the solute in a solution will increase the concentration of the solute in a solution by which the value $\Delta T_b$ will also get increased and vice-versa.

Increased in value of$\Delta T_b$ means that boiling point of solution will also get increased.

So, increase in concentration of solute in solution will increase the boiling point of the solution and vice-versa

Depression in freezing point:

$\Delta T_f=K_f\times molality$

$\Delta T_f=K_f\times \frac{\text{mass of solute}}{\text{Molar mass of solute}\times \text{Weight of solvent}}$

From the above expression we can say that :

$\Delta T_f\propto {\text{mass of solute}$

Increasing the mass of the solute in a solution will increase the concentration of the solute in a solution by which value $\Delta T_f$ will also get increased and vice-versa.

Increased in value of$\Delta T_f$ means that freezing point of solution will also get increased which means that more lowering in freezing point will take place.

So, increase in concentration of solute in solution will increase the lowering in freezing point of the solution and vice-versa