i) When placed in Hypotonic solution:

The size of the cell will increase when placed in a hypotonic solution. This occurs due to the phenomenon of osmosis or endosmosis, wherein the water moves towards a highly concentration solution. Hypotonic solution is not very concentrated and hence water moves away from this hypotonic solution towards the inside of the cell which is more concentrated causing the cell to swell.

ii) When placed in a Hypertonic solution:

The size of the cell will decrease when placed in a hypertonic solution. This occurs due to the phenomenon of osmosis or exosmosis, wherein the water moves towards a highly concentration solution. Hypertonic solution is very concentrated and hence water moves towards this hypertonic solution from the inside of the cell which is less concentrated to the outside which is more concentrated causing the cell to shrink.

iii) When placed in an isotonic solution:

The size of the cell remains the same when placed in an isotonic solution. This is because both the inside and outside of the cell are in the same concentration. Hence, there is no need for the water to move in either direction as equilibrium is already achieved.