The correct expression for osmotic pressure of the solution involving dissociation of the solute is

$π=\frac{in_2RT}{V}$

The correct answer is Option (4) → $π=\frac{in_2RT}{V}$

For solutions involving dissociation of the solute, the osmotic pressure must include the van’t Hoff factor (i).

The correct formula is:

$\pi = i \frac{n_2 RT}{V}$​

where

• $i$ = van’t Hoff factor
• $n_2$​ = number of moles of solute
• $R$ = gas constant
• $T$ = absolute temperature
• $V$ = volume of solution