Question

Consider the model of osmotic pressure as shown in Fig. 17.15. What if both sides contained a different pure solvent, each with a different vapor pressure? What would the system look like at equilibrium? Assume the different solvent molecules are able to pass through the membrane.

Short answer

The movement of molecules will occur from higher vapor pressure to lower vapor pressure until an equilibrium is reached.

Step-by-step solution

Osmotic pressure:

$\pi =\text{M}\times \text{R}\times \text{T}$

where$\pi$ is the osmotic pressure in atmospheres, M is the molarity of the solute, R is the gas law constant, and T is the Kelvin temperature.

Vapour pressure:

Since osmotic pressure depends on molar concentration which is directly dependent upon vapor pressure, hence the movement of molecules occurs from higher vapour pressure to lower vapour pressure.