In the following diagram, to prevent osmosis, if excess pressure is applied on one side of the semipermeable membrane (SPM), then I, II, III and IV are, respectively,

(A) Solution
(B) $P_{atm}$
(C) $Р_{atm}+П$
(D) Solvent

Choose the correct answer from the options given below:

(C), (B), (A), (D)

The correct answer is Option (4) → (C), (B), (A), (D)

Osmotic Pressure is the pressure that just stops the flow of solvent. The excess pressure that must be applied to a solution to prevent osmosis (i.e., to stop the passage of solvent molecules through a semipermeable membrane into the solution).

Osmotic pressure is a colligative property because it depends on the number of solute molecules and not on their identity.

For dilute solutions, osmotic pressure is proportional to the molarity, $C$, of the solution at a given temperature, $T$.

Thus:

$\pi = CRT$

Or $\pi = \frac{n_2}{V} RT$

Here,

$\pi$ = Osmotic pressure

$R$ = Gas constant

$V$ = Volume of a solution in litres

$n_2$ = Moles of solute