Question

Two beakers A and B contain plain water and concentrated sugar solution respectively. Equal number of dried raisins are kept in them for some time and then taken out.

a. Explain the reason for the difference in their physical appearance.

b. Categorise the two solutions as Hypotonic and Hypersonic.

Answer 1

Part (a): Changes in raisins:

1. Raisins present in beaker A are inside pure water.
   
2. Since the raisins are introduced in dry form, there is no water in the raisin.
   
3. The water level is higher towards the outside and hence water moves inside the raisin through osmosis to maintain an equilibrium concentration.
   
4. This swells up the dry raisin present inside the beaker A.
   
5. In the beaker B, there is a higher sugar concentration in the solution compared to the raisin.
   
6. This is why the water will further move out of the raisin making the raisin shrink more.
   
7. The raisin in beaker B will shrink as the water is lost till the equilibrium concentration is reached.
   

Part (b): Type of solution:

1. ​The plain water in beaker A is a hypotonic solution because the solute concentration of the surrounding solution is lower compared to that of raisin.
   
2. The concentrated sugar solution in beaker B is hypertonic because the solution has a higher concentration compared to the raisin.