What is an Unsaturated Solution?

Introduction

Unsaturated solutions are in need of more concentrations of solute molecules into the solution. There are different types of solvents that are able to break down a solute and shows significantly different physical properties than its original one. Once all the properties of the solute are assimilated into the solvent, a mutual resemblance of two different components is shared.

Types of saturated solutions

The types of solutions are as follows −

Figure 1: Types of saturated solutions

Unsaturated Solution

The unsaturated solution means a solvent can dissolve more concentration of solute particles. It also indicates that the solution has not reached at the point of saturation.

Surated Solution

The solution where solvents has absorbed the maximum amount of solute particles into its intermolecular distances known as saturated solution. In this case, a glass of water is able to dissolve 10g at its maximum limit at room temperature. Hence, this solution can be considered as saturated solution of sugar water. Because there are no more spaces left between water molecules to accommodate a single unit of sugar.

Supersaturated Solution

Supersaturated solution is the type of solution that goes beyond the level of saturation. For example, a glass of water dissolves maximum 10g amount of sugar and even though another 10g of sugar addition leads to the supersaturation of solution. Because there are no more spaces left between water molecules to accommodate the sugar molecules inside the intermolecular spaces of water results in solid sugar molecules are settled down at the bottom of the glass.

Preparation of Unsaturated Solutions

Solvents are the medium which could be solid, liquid, or gas in state and able to dissolve any solid, liquid, or gaseous particles into it as solute. The solution consists of few physical properties of solute as well as some properties of pure solvent.

For homogeneous solution both solvent and solute exists in the same state of matter, hence the physical properties of solution does not changes than its properties in pure state. For example, the refreshing solution is made using sugar, salt, and water; where one solvent and two solutes are present. These two solutes are homogenous and their physical shape is not retained once these two are mixed into a glass of water.

Figure 2: Preparation of supersaturated solution

Cuterjeans, A Supersaturated Solution, CC BY-SA 4.0

The preparation of supersaturated solution is a very simple process to determine the maximum limit of saturation for a specific solution. Thus, the process of making an unsaturated solution is considered as a solvent limiting process where solvent acts as a limiting agent to the amount of solute. For example, if a glass of water is able to dissolve 10g of sugar then only 2g has been poured into it. The solute does not get dissolved eventually that means the process of saturation remains completed. This defines the solvent cannot dissolve more solute and reaches to its supersaturation point.

Steps to change Unsaturated Solutions

The steps to change unsaturated solutions are divided into three classifications. The first step is by adding more solute inside the solvent to help it reach at the point of saturation. In this case, the solute must be poured inside the solvent and stir it until the solute is not dissolved. The second method is by heating the saturated solution.

By losing the attributes of the solvent, a saturated solution changes to a supersaturated state. The sugar and water solution when boiled loses the water content into vapour state. Hence, the volume of water decreases but the amount of solute remains same. Therefore, the unsaturated solution changes to a supersaturated one after some time.

Properties of Unsaturated Solutions

The properties of unsaturated solutions are as follows −

• The unsaturated solutions are very affected by the addition of different types of solutes.

• It has capability to intake more amount of solute particles as its solvent part remains with availability of vacant spaces in the intermolecular spaces between solvent molecules.

• Heating a saturated solution under confinement results in more intermolecular space between solvent molecules and more amounts of solute molecules can be dissolved into it. Hence, saturated solution can be converted into unsaturated solution by heating it under confinement.

These are some of the properties are found for an unsaturated solution.

Difference between Saturated and Unsaturated Solutions

Saturated solution	Unsaturated solution
When the temperature of the saturated solution is increased then it covert into unsaturated solution which need more amount of solute to get back saturation point.	When unsaturated solution is heated no significant change occurs unless the requirement of more amount of solute particles to achieve saturation point.
The time when the temperature starts to go down the saturation point of the solution starts to go down and it turns supersaturated solution at lower temperature with excess solute particles at the bottom of the solution.	The point of unsaturation decreases and the solution achieves saturation point very easily when the temperature starts to come down below a certain point.
The precipitation of solute is visible as the solvent has no more space to dissolve the solute particles.	There is a significant amount of space left into the solvent to dissolve the solute. Therefore, it is a zero precipitation case.

Table 1: Difference between saturated and unsaturated solutions

Conclusion

The tutorial explains the meaning of saturated solutions found in the day to day activities. The learners are able to understand the ways a solution can be unsaturated. Some steps are able to discuss the basic methods of changing the state of an unsaturated solution. The process is obtained by changing the factors that influence the level of saturation.

FAQs

Q1. What are the factors that affect the solubility of a solvent?

Ans. Two major factors are known to affect the solubility of a solute. These two factors are temperature and pressure on the solution.

Q2. What is meant by sparingly soluble liquid?

Ans. This type of liquid is not able to dissolve solute particles completely using intermolecular spaces due to various physical properties of solute as well as solvent. Henceforth, the solute is partly dissolved and a large amount of solute is not able to dissolve into the solvent.

Q3. In what state is a polar solute able to be dissolved?

Ans. The polar nature of the solvent helps to dissolve a polar solute using polar molecular or ionic interactions. Most of the soluble solute exists in this state where the process of assimilation is likely going to happen.