ICSE Class 10 Answered

Tonicity is the relative concentration of the solutions that determine the direction and the extent of diffusion. Based on tonicity the three types of solutions are:

1. Isotonic Solution: The relative concentration of water molecules and the solute on either side of the cell membrane is the same. Hence there is no net movement of water molecules.



2. Hypotonic solution: In this condition, the solution outside the cell has a lower solute concentration than the fluids inside the cell. Thus, endosmosis takes place i.e. water enters the cell and thus the cell becomes turgid.



3. Hypertonic solution: In this condition, the solution outside the cell has a higher solute concentration than the fluids inside the cell. Therefore exosmosis takes place i.e. water moves out from the cell and thus the cell becomes flaccid.