Saturation

Table salt (NaCl) readily dissolves in water. Suppose that you have a beaker of water to which you add some salt, stirring until it dissolves. So you add more and that dissolves. You keep adding more and more salt, eventually reaching a point where no more of the salt will dissolve no matter how long or how vigorously you stir it. Saturation is a measure of the point reached when you can't dissolve any more solute in a solvent.

To introduce this concept of saturation, please watch the video below.

To summarize what you have seen in the video above, when the solution equilibrium point is reached and no more solute will dissolve, the solution is said to be saturated. A saturated solution is a solution that contains the maximum amount of solute that is capable of being dissolved. At 20°C, the maximum amount of NaCl that will dissolve in 100. g of water is 36.0 g. If any more NaCl is added past that point, it will not dissolve because the solution is saturated. An unsaturated solution is a solution that contains less than the maximum amount of solute that is capable of being dissolved. The picture below illustrates the above process and shows the distinction between unsaturated and saturated.

Saturated And Unsaturated. See description

Saturated and Unsaturated description

Solutions can also become supersaturated, where the amount of solute dissolved exceeds its solubility. They occur frequently in geological and meteorological processes. Supersaturated systems are unstable, and eventually, the solute will precipitate until a saturated solution is regenerated. Sweet tea is a great example of a supersaturated solution. How do you add so much sugar to make sweet tea sweet enough? You have to heat the solution because temperature increases the amount of sugar that will dissolve in the sweet tea solution.

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