(a) Define the terms osmosis and osmotic pressure. Is the osmotic pressure of a solution a colligative property? Explain. 

(b) Calculate the boiling point of a solution prepared by adding 15.00 g of NaCl to 250.0 g of water. (K_b for water = 0.512 K kg mol^-1), (Molar mass of NaCl = 58.44 g)

(a) Osmosis: The process of flow of solvent molecules from pure solvent to a solution or from a solution of lower concentration to a solution of higher concentration through a semi-permeable membrane is called osmosis. 

Osmotic Pressure: The pressure required to just stop the flow of solvent due to osmosis is called osmotic pressure (π) of the solution. 

 Yes, the osmotic pressure of a solution is a colligative property. The osmotic pressure is expressed as. 

 
Where,  

π  = osmotic pressure 

n = number of moles of solute 

V = volume of solution 

T = temperature 

From the equation, it is clear that osmotic pressure depends on upon the number of moles of solute ‘n’ irrespective of the nature of the solute. 

Hence, osmotic pressure is a colligative property. 

(b) Given

 K_b = 0.512 k kg mol^-1

w₂ = 15.00 g 

w₁ = 250.0 g 

M₂ = 58.44 g 

Using the formula,