Name: Solid Solutions
Uploaded: 2019-07-19
Duration: 2 min 56 s
Description: Solutions can be categorized as solid, liquid, and gaseous based on the physical states of solvents and solutes. In this video, let's learn about solid solutions.

Question

Describe various laws of osmotic pressure and derive van't Hoff equation. Show that osmotic pressure is a colligative property.

Accepted Answer

Van't Hoff's theory of osmotic pressure:- Solute particles in dilute solutions possess kinetic energy and move in random directions in solutions. Thus, they have similar behaviour as that of gas molecules.

Van't Hoff's Boyle's law of solution:- At constant temperature, the osmotic pressure of the dilute solution is directly proportional to its molar concentration or inversely proportional to volume.

$π = CRT παC π = \frac{n}{v} RT πα \frac{1}{v}$ (at constant temperature)

Van't Hoff's Charle's law :- The osmotic pressure of the dilute solution is directly proportional to the absolute temperature, if the concentration of the solution is kept constant. Thus,

$παT \frac{π}{T} = constant$ (at constant concentration)

Van't Hoff's equation :- For n moles of solute dissolved in V litres of the solution, van't Hoff equation can be written as:

$παT (Charle' s law) πα \frac{1}{v} (Boyle' s law) πα \frac{T}{v} πv = KT πv = RT For one mole for n moles, π = \frac{nRT}{v} π = CRT As π α n (moles of solute) .$

Osmotic pressure is a colligative property as it depends on the number of solute particles, regardless of their composition, compared to the total number of particles present in the solution, and osmotic pressure depends on the concentration of the solution.

Describe various laws of osmotic pressure and derive van't Hoff equation. Show that osmotic pressure is a colligative property.

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