Saturated Solution Definition and Examples

A saturated solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent. ​The additional solute will not dissolve in a saturated solution.

The amount of solute that can be dissolved in a solvent to form a saturated solution depends on a variety of factors. The most important factors are:

• Temperature: Solubility increases with temperature. For example, you can dissolve much more salt in hot water than in cold water.
• Pressure: Increasing pressure can force more solute into solution. This is commonly used to dissolve gases into liquids.
• Chemical Composition: The nature of the solute and solvent and the presence of other chemicals in a solution affects solubility. For example, you can dissolve much more sugar in water than salt in water. Ethanol and water are completely soluble in each other.

Examples of Saturated Solutions

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What Is an Unsaturated Solution?

By Anne Marie Helmenstine, Ph.D.

You encounter saturated solutions in daily life, not just in a chemistry lab. Also, the solvent does not need to be water. Here are some common examples:

• A soda is a saturated solution of carbon dioxide in water. This is why, when the pressure is released, carbon dioxide gas forms bubbles.
• Adding chocolate powder to milk so that it stops dissolving forms a saturated solution.
• Salt can be added to melted butter or oil to the point where the salt grains stop dissolving, forming a saturated solution.
• If you add enough sugar to your coffee or tea, you can form a saturated solution. You'll know you've reached the saturation point when the sugar stops dissolving. Hot tea or coffee allows much more sugar to be dissolved than you can add to a cold beverage.
• Sugar can be added to vinegar to form a saturated solution.

Things That Will Not Form Saturated Solutions

If one substance will not dissolve into another, you cannot form a saturated solution. For example, when you mix salt and pepper, neither dissolves in the other. All you get is a mixture. Mixing oil and water together will not form a saturated solution because one liquid does not dissolve in the other.

How to Make a Saturated Solution

There's more than one way to make a saturated solution. You can prepare it from scratch, saturate an unsaturated solution, or force a supersaturated solution to lose some solute.

1. Add solute to a liquid until no more dissolves.
2. Evaporate solvent from a solution until it becomes saturated. Once the solution starts to crystallize or precipitate, the solution is saturated.
3. Add a seed crystal to a supersaturated solution so extra solute will grow onto the crystal, leaving a saturated solution.

What Is a Supersaturated Solution?

The definition of a supersaturated solution is one which contains more dissolved solute than could ordinarily dissolve into the solvent. A minor disturbance of the solution or introduction of a "seed" or tiny crystal of solute will force crystallization of excess solute. One way supersaturation can occur is by carefully cooling a saturated solution. If there is no nucleation point for crystal formation, the excess solute may remain in solution.