# Does osmotic pressure depend on the quantities of the outer membrane solvent?

$$\pi V = nRT$$
What is the osmotic pressure at $$\pu{25^oC}$$ of an aqueous solution of 0.0010 M $$\ce{C12H22O11}$$ (sucrose)?
We just need to substitute the data into equation (13.4)

$$\pi = \frac{\pu{0.0010 mol} \times \pu{0.08206 atm L mol-1 K-1 }\times \pu{298 K}}{1L} \\ \pi = \pu{0.024 atm} (\pu{18 mmHg)}$$

I'm a bit confused about osmotic pressure.

I am not sure what $$\pi$$ represents in the example. Is this pressure the pressure needed to prevent the flow of solvent through a membrane into the solution? Why isn't it considering the amount of solvent outside? for example, if I had 1000L of outer water in a sucrose solution, wouldn't a different osmotic pressure be needed than if I only had 50L of outer water?

• Is this pressure the pressure needed to prevent the flow of solvent through a membrane into the solution? - Yes it is. And it depends on the solvent volume just indirectly, if it causes hydrostatic pressure on the solvent side. Commented Apr 25 at 17:53