Difference Between Saturated and Supersaturated Solution

Main Difference – Saturated vs Supersaturated Solution

A solution a liquid mixture in which a solute is uniformly distributed within the major component or the solvent. Solutions can be divided into several types depending on the chemical and physical properties of those solutions. Saturated solutions and supersaturated solutions are two such types. A saturated solution is composed of the maximum amount of solutes that can be dissolved in a solvent at a given temperature. A supersaturated solution is composed of more than the amount of solutes that can be dissolved in a solvent at the same temperature. This is the main difference between saturated and supersaturated solution.

Key Areas Covered

1. What is a Saturated Solution
      – Definition, Factors Affecting Saturation
2. What is a Supersaturated Solution
     – Definition, Preparation
3. What is the Difference Between Saturated and Supersaturated Solution
     – Comparison of Key Differences

Key Terms: Polarity, Precipitation, Saturated Solution, Saturation, Solubility, Solute, Solvent, Supersaturated Solution

What is a Saturated Solution

A saturated solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent. This means no more solutes can be dissolved in that solution. If more solutes are added to this solution, it leaves the excess solutes at the bottom of the container.

Figure 01: Adding sugar to water until it no longer dissolves creates a saturated solution.

However, the amount of solute that can be dissolved in a particular solvent depends on several factors as given below.

• Polarity – Polar solutes dissolve in polar solvents. Nonpolar solutes dissolve in nonpolar solvents.
• Temperature – Solubility of a solute in a particular solvent increases with the increasing temperature
• Pressure – By increasing the pressure, more solutes can be dissolved in the solvent due to the force applied on the solutes.
• Surface area – Finely powdered solutes have a higher solubility than large particles.
• Stirring – Stirring will increase the solubility of a solute in a solvent.
• Chemical composition – The chemical compositions of solute and the solvent also affects the solubility.

What is a Supersaturated Solution

A supersaturated solution is a solution that contains more solute than the solvent can dissolve. A solution can be brought to the state of supersaturation by changing the normal conditions of a solution. Then the solution will have more solutes than usual at a given temperature. Usually, when a solution gets saturated, the excess amount of solute is deposited at the bottom of the container. But in supersaturated solutions, there is no deposition or precipitation at the bottom.

Figure 2: Supersaturation of sugar in water can be used to make rock candy

In the formation of a supersaturated solution, special conditions have to be provided to the solution. Since the solubility of a solute is directly affected by the temperature of the solvent, the temperature dependence solubility can be used as a strategy to make a supersaturated solution. Here, we can first dissolve the maximum amount of solute in the solvent at room temperature. Then, more solutes can be dissolved by increasing the heat of the solvent. If we cool this solution at a rate that is faster than the rate of precipitation of solute, the solution becomes supersaturated. Pressure and volume are other factors that can be changed in order to obtain a supersaturated solution.

Difference Between Saturated and Supersaturated Solution

Definition

Saturated Solution: A saturated solution is a solution is a chemical solution containing the maximum concentration of a solute dissolved in the solvent.

Supersaturated Solution: A supersaturated solution is a solution which contains more dissolved solute than could ordinarily dissolve into the solvent.

Amount of Solute

Saturated Solution: A saturated solution has the maximum amount of solutes that can be dissolved in the solvent at room temperature.

Supersaturated Solution: A supersaturated solution has more than the maximum amount of solutes that can be dissolved in the solvent at room temperature.

Preparation

Saturated Solution: A saturated solution can be prepared by evaporating a solvent from a solution until the solute begins to crystallize or precipitate.

Supersaturated Solution: A supersaturated solution can be prepared by adding the solute in excess at a high temperature and suddenly cooling down at a rate that is faster than the precipitation of the solute.

Precipitation

Saturated Solution: A saturated solution does not show precipitation at the bottom of the container.

Supersaturated Solution: A supersaturated solution shows precipitation at the bottom of the container if the physical conditions are changed.

Conclusion

A solution is a mixture of a solute and a solvent. In most solutions we know, the solute is the minor component and solvent is the major component. But a saturated solution has the maximum amount of solutes that can be dissolved at a given temperature. We can make a supersaturated solution out of a saturated solution. Then, the amount of solute present in the supersaturated solution will be higher. The main difference between saturated and supersaturated solution is that, at a given temperature, a saturated solution has a maximum amount of solutes in the solution whereas a supersaturated solution has more than the maximum amount of solutes in the solution.

References:

1. “Saturated Solution: Definition & Examples.” Study.com, Available here.
2. “Supersaturated Solution: Definition & Example.” Study.com,  Available here.
3. “Supersaturation.” Wikipedia, Wikimedia Foundation, 11 Oct. 2017, Available here.
4. “Types of Saturation.” Chemistry LibreTexts, Libretexts, 21 July 2016, Available here.

Image Courtesy:

1. “Spoon Sugar Solution with Glass” By APN MJM – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Rock-Candy-Sticks” By Evan-Amos – Own work (CC BY-SA 3.0) via Commons Wikimedia