(a) Difference between sol, solution and suspension.
(b) What are saturated and unsaturated solutions?

Hint :First we will understand the properties of sol, solution and suspense, then differentiate between these three. Saturation and unsaturation of a solution can be determined with the help of solubility of a solute (compound that is to be dissolved) in the solvent (compound or solution in which the solute is dissolved).

Complete Step By Step Answer:
Sol- Sol is a heterogeneous mixture in which the size of the particles is too small and cannot be seen with naked eyes. It is quite stable and hence, does not settle down the solution when left undisturbed. The particles cannot be separated out from solution with the help of filtration process.
Solution- It is a homogeneous mixture and the particles present in it cannot be seen with naked eyes. It does not scatter the beam of light which is passing through it. The particles cannot be separated out from solution with the help of filtration process.
Suspension- It is also a heterogeneous mixture in which the particle size is quite large and can be seen with naked eyes. It scatters the beam of light. The particles settle down when left undisturbed. Solute can be separated out using filtration.
(b) Saturated solutions are those solutions in which the amount of solute in the solvent reaches the saturation level.
Unsaturated solutions are those solutions in which the amount of solute in the solvent is less than the saturation level.

Note :
We should note that if the solution is unsaturated, the solute has not reached the saturation level and hence, more solute can be dissolved in the solution till it becomes saturated in nature. If the solution is saturated, then more solute cannot be dissolved in water as it will remain as crystals or solid in the solution.