Final answer:
A saturated solution contains the maximum amount of solute that can be dissolved in a solvent at a given temperature, while an unsaturated solution has less than this maximum amount. Supersaturated solutions have more solute than the normal limit but are unstable.
Step-by-step explanation:
A saturated solution is one in which the maximum amount of solute has been dissolved in a given amount of solvent at a specific temperature. For instance, at 20°C, 36.0 g of NaCl in 100 g of water represents a saturated solution; any additional NaCl will not dissolve because the solution has reached its solubility limit. Contrastingly, an unsaturated solution contains less solute than this maximum point. A common way to exceed this maximum and create a supersaturated solution is by heating the solvent, dissolving more solute, and then slowly cooling the solution. However, supersaturated solutions are unstable, and the excess solute will precipitate if disturbed.
Differentiating between saturated and unsaturated solutions can be done by adding more solute; if it doesn't dissolve, the solution was already saturated. If the added solute does dissolve, it was unsaturated. A visible indication of saturation is the presence of undissolved solute at the solution's bottom after equilibrium is reached.