Question

Why raisins get shrink in hypotonic solution but when kept in hypertonic it swells

Answer 1

raisins get swelled up in hypertonic solution because the solution's osmotic pressure is more than that of raisin and ...for hypotonic its osmotic pressure is low than raisins

Answer 2

First of all your question is wrong. It must that Why raisins swell in hypotonic solution but when kept in hypertonic it shrinks.

So now, You must know what is Osmosis. Osmosis is the movement of water or solvent molecules from the region of their higher concentration(hypertonic) to the region of their lower concentration(hypotonic) through a semi-permeable membrane. Now focus on the raisin. If you put it in water it will swell because the raisin has less concentration of water than the surrounding water and therefore water will move inside due to osmosis and this type of osmosis is termed as Endosmosis.