Question

(i) Prove that osmotic pressure is a colligative property.
(ii) Calculate the molar concentration of urea solution if it exerts an osmotic pressure of 2.45 atmosphere at 300K. [R= 0.0821 l. atm. $mo{l}^1$ $K^{-1}$]

Answer 1

i) $\pi =CRT$ ; Where $\pi =$ osmotic pressure

and $C=$ Molarity of the solution

Colligative property depend on number of solutes in a solution. Now, $\pi$ depends also molarity of the solution.

ii) $\pi =CRT$

$\Rightarrow 2.45=C\times 0.0821\times 300$

$\Rightarrow C=0.1M$