Question

What is osmotic pressure? What is isosmotic? What is hypoosmotic?

Answer 1

Hint: Suppose two solutions are separated by a semipermeable membrane and one of the solutions has a high concentration and the second one has low concentration, then there is a flow of solvent from low concentration to high concentration. This process is opposed by pressure.

Complete answer:
Let us first understand the term osmosis to understand the osmotic pressure. In simple terms, we can say that osmosis is a process of flow of only solvent molecules through a semipermeable membrane.
Suppose two solutions are separated by a semipermeable membrane and one of the solutions has a high concentration and the second one has low concentration, then there is a flow of solvent from low concentration to high concentration. This process is known as osmosis. Now, when the osmosis is occurring there is a pressure applied by the solution to an inflow of the solvent particles, and this pressure is known as osmotic pressure. It is represented by pi ($\pi $).
If the solutions on both sides of the semi-permeable membrane have the same concentration then they will apply the same osmotic pressure and the amount of solute and solvent will be the same, so this system is known as iso-osmotic solutions.
When one solution has lower osmotic pressure as compared to the osmotic pressure of the other, then it is known as a hypo-osmotic solution.

Note:
There is another term hyper-osmotic solution in which one solution has higher osmotic pressure as compared to the osmotic pressure of the other. There is another term isotonic solution which is similar to iso-osmotic solutions.