How does osmotic pressure depend on molality of the solution?

Answer:
osmotic pressure is proportional to the molarity, C of the solution at a given temperature T. Thus: Π = C R T 
Here Π is the osmotic pressure and R is the gas constant. 
Π = (n₂ /V) R T 
Here V is volume of a solution in litres containing n2 moles of solute. If w2 grams of solute, of molar mass, M2 is present in the solution, then n₂ = w₂ / M₂ and we can write,

 in a dilute aqueous solution molarity is equal to molality.
c = m when p = 1 and solution is dilute.
$\mathrm{\pi } = {\mathrm{n}}_{\mathrm{B}} \frac{\mathrm{RT}}{\mathrm{V}} = \mathrm{cRT} = \mathrm{mRT}$

The osmotic pressure will increase with an increase in molality of the solution at a given temperature.