Solutions
Isotonic solutions
Two solutions having same osmotic pressure at a given temperature are known as isotonic solutions.
In the case of isotonic solutions, no osmosis takes place between them.
Example –
The sodium chloride solution which is 0.9% (mass/volume) of sodium chloride solution has equivalent osmotic pressure to the fluid found inside the blood cells.
This is the cause that 0.9% of sodium chloride solution, i.e. normal saline is injected intravenously in the case of dehydration and other emergency.
Saline (solutions) containing more than 0.9%(mass/volume) of sodium chloride is called hypertonic.
Saline (solutions) containing less than 0.9%(mass/volume) of sodium chloride is called hypotonic.
If blood cell is kept in a solution containing more than 0.9% of sodium chloride, the fluid inside the blood cells will flow out because of osmosis. And due to loss of water; blood cells would collapse.
On the other hand; if blood cell is kept in a solution containing less than 0.9% of sodium chloride, water will flow inside the blood cells because of osmosis, resulting in swelling of blood cells.
There is a medical condition called edema, in which people experience water retention in tissue cells and intermolecular spaces resulting in puffiness or swelling body. This happens to the people taking more salt or salty food. Taking of more salty food increase the concentration of salt in tissues; this creates imbalance in osmotic pressure between fluid inside the blood cells and tissues. And to maintain the equilibrium, water from outside the tissue flows in the tissues and intermolecular spaces in the body.
Meat is preserved by salting. By salting bacterium on meat loses water because of osmosis and dies. Thus, salting protects the meat against bacterium action.
Sugar is added to fruits for preservation. By adding sugar to the fruits, bacterium over fruits loses water because of osmosis due to imbalance in osmotic pressure, and dies.
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