Isotonic, Hypertonic and Hypotonic Solutions

i. Isotonic solutions : Two or more solutions having the same osmotic pressure are said to be isotonic solutions.

For example, a 0.1 M urea solution and a 0.1 M sucrose solution are isotonic because their osmotic pressures are equal. Such solutions have the same molar concentrations but different concentrations in g/L. If these solutions are separated by a semipermeable membrane, there is no flow of solvent in either direction.

ii. Hypertonic and hypotonic solutions : If two solutions have unequal osmotic pressures, the more concentrated solution with the higher osmotic pressure is said to be the hypertonic solution. The more dilute solution, exhibiting the lower osmotic pressure, is said to be the hypotonic solution. …