Which of the following colligative properties affects the movement of solvent across a semipermeable membrane?

The movement of solvent across a semipermeable membrane is primarily influenced by osmotic pressure. Osmosis is the process by which solvent moves from an area of lower solute concentration to an area of higher solute concentration through a semipermeable membrane. This movement continues until equilibrium is achieved, where the concentrations on both sides of the membrane become equal.

Osmotic pressure is specifically defined as the pressure required to stop the flow of solvent into the area with a higher solute concentration, effectively balancing the concentrations on both sides of the membrane. It reflects the tendency of water (or other solvents) to move in response to differences in solute concentrations, making it a colligative property that is directly related to the number of solute particles in solution.

While boiling point elevation, freezing point depression, and concentration of the solute are related to solutions, they do not directly govern the actual movement of solvent across a membrane in the way that osmotic pressure does. Boiling and freezing point changes pertain to temperature changes in the solution rather than directional solvent movement, and while concentration is crucial, it does not encapsulate the dynamic process of movement across membranes without the pressure context provided by osmotic pressure.