Take a glass of water and add a tablespoon of flour in it. Now stir it well. What do you see? Does water and flour mixture appear clear or a turbid (unclear)? Yes, you are right. The mixture appears turbid. What do you think, what have you prepared? A solution, a colloid or a suspension? Well if you observe this mixture for some more time then you will see that particles of flour slowly settle down at the bottom of the glass. This indicates that it is a suspension. We will discuss suspensions in detail from a chemistry point of view. With this we will discuss solutions, colloids, and solubility as well in comparison with suspensions. So that it will help you to distinguish mixtures as suspension, solution, or colloids.
What is Suspension?
A suspension is a heterogeneous mixture in which the solute particles do not dissolve but remain suspended throughout the bulk of the medium. In other words, suspensions are non – homogeneous systems in which solids are dispersed in liquids. Constituent particles of a suspension are large enough that gravity can pull them down out of dispersion medium. These particles can be easily separated by the filtration method from the dispersion medium. Size of particles in suspension is at least 100 times larger than particles of solution.
Examples of Suspension
Some common examples of suspension are listed below –
Mixture of flour and water
Mixture of chalk and water
Mixture of sand and water
Paints (water based)
Mixture of Slaked lime (Calcium hydroxide) in water
Mixture of magnesium hydroxide and water (Milk of Magnesia)
Some salad dressings such as thousand island, honey mustard dressing
Properties of Suspension
General characteristics and properties of suspensions are listed below –
It is a heterogeneous mixture.
Constituent particles of suspension mixture can be seen by naked eyes.
Size of particles in suspension is more than 100nm.
Suspension shows Tyndall effect. It means particles of a suspension scatter a beam of light passing through it and make its path visible.
If suspension is left undisturbed, its particles settle down. It shows that suspension is an unstable mixture. In this condition suspension does not show Tyndall effect.
Constituent particles of a suspension can be separated by filtration.
What is a Solution?
A solution is a homogeneous mixture of two or more substances. A solution has a solute and solvent as its components. The component of the solution which dissolves the other component in it is called solvent while the other component which gets dissolved in the solvent is called solute. Generally, in a solution solute is present in a lesser amount than solvent.
Examples of solution
You can see many examples of solutions in your daily life. Few examples of solution are listed below –
Mixture of sugar and water.
Tincture of iodine (solution of iodine in alcohol)
Air (a homogeneous solution of various gases)
Alloys (Mixture of two or more metals or a metal and a non – metal which cannot be separated by physical methods. For example – Brass, Stainless steel etc.)
Properties of Solution
Solution shows following properties –
It is a homogeneous mixture.
Size of the particles in solution is less than 1 nm in diameter.
Particles of solution cannot be seen by naked eyes.
Particles of solution cannot be separated by simple physical methods of separation such as filtration.
What is a Concentrated Solution?
Proportion of the solute and solvent can be varied. Depending upon the amount of solute present in a solution, it can be called a dilute, concentrated or a saturated solution.
Dilute and concentrated are comparative terms. A solution which contains a relatively larger amount of solute is called a concentrated solution while a solution which contains a relatively smaller amount of solute is called a dilute solution. On the other hand, at any particular temperature, a solution that has dissolved as much solute as it is capable of dissolving, is called a saturated solution.
What is Solubility?
The amount of solute present in the saturated solution at the particular temperature is called solubility of that saturated solution. Thus, solubility is the ability of the solute to get dissolved in a solvent at a particular temperature.
According to the IUPAC definition, solubility is the analytical composition of a saturated solution expressed as a proportion of a designated solute in a designated solvent.
Solubility can be expressed in various units of concentration such as molarity, molality, mole fraction, mole ratio etc.
What is a Colloid?
A heterogeneous mixture in which particles are uniformly spread throughout the solution is called a colloid. It is also called a colloidal solution. The term colloid is sometimes used particularly for dispersed substance alone in the colloidal solution, but the term colloidal suspension refers unambiguously to the overall mixture. Although suspension and colloidal suspension (solution) both are different types of mixtures. It appears to be homogeneous because of its smaller particle size than suspension. It also shows the Tyndall effect.
Some common examples of colloids are listed below in tabular form with their dispersion phase, dispersion medium and type –
Properties of Colloids are listed below –
A colloid is a heterogeneous mixture.
Particles of colloids are not visible by naked eyes.
In colloids, dispersed phase particles have a diameter between 1 – 100 nm (approximately).
They show the Tyndall effect.
In colloids, dispersed particles do not settle down when left undisturbed.
Colloids are stable mixtures.
In colloids, dispersed phase and dispersion medium cannot be separated by filtration.
In colloids, dispersed particles show Brownian movement.
Comparison between properties of suspension, colloids and solution is given below in tabular form for your better conceptual clarity –
This ends our coverage on Suspensions. We hope you enjoyed learning and were able to grasp the concepts. We hope after reading this article you will be able to distinguish suspensions, colloidal solutions and solutions. If you are looking for solutions to NCERT Textbook problems based on this topic, then log on to Vedantu website or download Vedantu Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Revision notes, Mock Tests and much more.