What is osmotic pressure?
Answers
Osmotic Pressure:-
⇒ The process of flow of solvent molecules from pure solvent to solution or from solution of lower concentration to solution of higher concentration through a semi-permeable membrane is called osmosis.
⇒ The pressure required to just stop the flow of solvent due to osmosis is called osmotic pressure (π) of the solution.
⇒ If a large amount of pressure is required to stop the osmosis, solution is said to have high osmotic pressure.
⇒ If only a small amount of pressure is sufficient to stop the osmosis, solution is said to have low osmotic pressure.
Applications of osmotic pressure are:-
1. Osmotic pressure is the basis of filtering; it is called reverse osmosis, a process commonly used to purify water. Reverse osmosis desalinates fresh water from ocean salt water.
2. Osmotic pressure is necessary for many plant functions (water transport in plants). It is the resulting turgor pressure on the cell wall that allows herbaceous plants to stand upright.
3. For the calculation of molecular weight by using colligative properties, osmotic pressure is the most preferred property.
4. Osmotic pressure is also used to generate electric power: Osmotic flow of fresh water into the seawater side forces the latter up through a riser containing a turbine connected to a generator, thus providing a constant and fuel-less source of electricity.
5. It is also used in food preservation. E.g. sauce, jellys, pickles, etc.
Osmotic Pressure- Osmotic pressure is due to presence of solute in the solution. In other words it equals to the pressure required to prevent the water from diffusing in hypertonic solution.
•Osmotic pressure of pure water is zero
•Osmetic pressure of a solution is directly proportional to the concentration of solute in it.
•Osmotic pressure of a solution is measured by osmometer.
•The osmotic pressure of electrolyte is higher than that of non electrolytes.
•When the water moves into the cell during osmosis it is called endoosmosis.
Example- Swelling of Raisins placed in Water.
•When the water moves out of the cell then it is called exosmosis.
Example- Shrinking of swollen raisins in highly concentrated sugar solution.