Final answer:
Osmotic pressure is a colligative property of solutions, which occurs when two solutions of different concentration are separated by a semipermeable membrane. It is the pressure required to halt the osmosis of solvent.
Step-by-step explanation:
Osmotic pressure is a colligative property of solutions. It occurs when two solutions of different concentration are separated by a semipermeable membrane. The net flow of solvent through the membrane, known as osmosis, is driven by the difference in solute concentration. This results in the generation of osmotic pressure, which is the pressure required to halt the osmosis of solvent.