Environmental Chemistry


The suspension is a homogenous mixture of particles with a diameter greater than 1000 nm. These particles are visible to the naked eye. In this sort of compounds mixture, all the components mix together and, all the particles are visible under the microscope. The suspension is a heterogeneous mixture of solid particles that are large enough for sedimentation. Here, the particles of the solute do not dissolve in the solvent but are rather suspended. The suspended particles are large enough to scatter the light rays and, the path of the light rays is visible through it.



Definition of Suspension

In chemistry, the suspension is a heterogeneous mixture of a fluid that includes solid particles that are sufficiently large for sedimentation. These particles may be visible to the naked eye. Usually, they are larger than one micrometre, and may gradually settle, but the mixture is only known as a suspension when and, while the particles do not settle down.

If we take a glass of water and mix the mud in it, it will form a heterogeneous mixture. The components of these mixtures are clearly visible to the naked eye. After a while, you can observe that the particles of mud slowly settle down because of gravity. You can see that the particles in suspension are much bigger than the particles in the solution.

Properties of Suspension

General characteristics and the properties of suspensions are:

1)The suspension is a heterogeneous mixture in which solvent molecules do not dissolve. They are suspended throughout the solvent in bulk and are left to float loosely in the medium. The internal phase (solid) is distributed in the external phase (fluid) by means of mechanical agitation, through the use of some excipients or suspended agents.

2)The sand in the water would be an example of a suspension. The suspended particles are visible under a microscope and will settle down over time if left undisturbed. It shows the difference between the suspension and the colloid, in which the suspended particles are smaller and do not settle.

3)The suspension of liquid droplets or of small solid particles in a gas is aerosol. In the atmosphere, suspended particles are called particulate matter and consist of fine dust and soot particles, sea salt, biogenic and volcanogenic sulphate, nitrates and cloud droplets.

4)Suspensions categorize on the basis of the dispersed phase and the dispersion medium, where the former is basically Solid, and the latter may be either solid, liquid or gas.

5)In modern chemical process industries, many novel suspensions production involves using high-shear mixing techniques. Suspensions are thermodynamically unstable but can be stable over a longer period of time, kinetically, which defines the suspension’s shelf life.

6)”Dispersion stability is the ability of a dispersion to resist any change in its properties over time.”

7)The size of the solvent particles in the suspension is quite large. Their size is usually more than 100 mm in diameter.

8)Suspension particles are clearly visible to the naked eye. Suspension particles do not pass through the filter paper. Hence the filtration process can separate the suspension. Because of the large particle size, the suspension can scatter the beam of light passing through it.

Examples of Suspensions

Below given are a few examples of suspensions;

  1. Mud in Water
  2. Turpentine oil in paint dyes
  3. Chalk in water
  4. Slaked lime for whitewashing
  5. Milk of magnesia
  6. Sand particles suspended in the water.
  7. Kimchi suspended on vinegar.

What is a Solution?

A solution is a homogenous combination of two or more substances. A solution has the solvent and the solute as its bases. Part of the solution that dissolves the other component is called the solvent, and the other component that dissolves in the solvent is called the solute. Besides, in a solution, a solute is present in a lesser amount than the solvent.

Properties of Solution

The solution shows various properties, given below are a few properties:

  1. It is a homogeneous mixture.
  2. The sample size of the solution is less than 1 nm in diameter.
  3. Particles in the solution are invisible to the naked eyes.
  4. Separation of solution particles is not possible by basic physical separation processes, such as filtration.

Examples of Solution

You can see a lot of examples of solutions in your daily life. Here are a few examples of a solution –

  1. A combination of sugar and water.
  2. Tincture of iodine (iodine solution of alcohol)
  3. Soda water
  4. Air (homogeneous solution of different gases)
  5. Alloys (a mixture of two or more metals or metals and non-metals which is not possible to separate by physical means, e.g. brass, stainless steel, etc.)

What is a Concentrated Solution?

The proportion of solutes and solvents may vary. On the basis of the grading of solute present in the solution, it may be dilute, concentrated or saturated. Diluted and concentrated are comparative terms.

A solution that has a relatively higher volume of solute is known as a concentrated solution, whereas, the solution containing a relatively less amount of solute is called the dilute solution. On the other hand, a solvent that has dissolved as much solute as it can dissolve at any given temperature is termed a saturated solution.

What is Solubility?

The volume of a solute present in the solution at a particular temperature is known as the solubility of the saturated solution.  Thus, solubility is the ability of the liquid to dissolve at a given temperature in a solvent. According to the IUPAC, solubility is an analytical composition of a saturated solution that defines the proportion of a designated solute in a specified solvent.

Molarity, Molality, Mole Fraction, Mole Ratio, etc., are different concentration units that can express the solubility.

What is Colloid?

A heterogeneous mixture in which the particles equally spread in the solution is called a colloid or colloidal solution. The term colloid is often used in particular for the scattered material alone in the colloidal solution, but the term colloidal suspension usually refers to the entire mixture.

Although suspension and colloidal suspension (solution) are also different types of mixtures, It tends to be homogeneous due to a smaller particle size than the suspension. It also reflects the Tyndall effect.

FAQs about Suspension

Q1. What are the different types of colloidal solutions?

Answer. There are various types of colloidal solutions they are:

  • Aerosols: Solid or Liquid combination with gas, an example of such is fog (liquid in gas).
  • Gel: liquid in solid; an example: Fruit jelly.
  • Sols: Solid combined with a liquid such as paint.
  • Emulsion: Liquid with liquid; an example of this is: oil and water.

Q2. What is the difference between suspension and colloids?

Answer. The difference between suspension and colloids are;


  • It’s a type of heterogeneous solution.
  • Particle sizes larger than 1000 nm.
  • Particles settle well.
  • The filtering process can separate it.
  • It may scatter light.
  • It is easily visible through the naked eye.


  • It is a type of homogenous solution.
  • The particle scale varies from 1 to 1000 nm.
  • Particles basically do not separate.
  • The filtering process can also not separate it.
  • Shows the Tyndall effect (scatters light).
  • It is not visible to the naked eye.

Q3. Give a few examples of suspension.

Answer. The most common examples include a mixture of chalk and water, muddy water, a mixture of flour and water, a mixture of dust particles and air, fog, magnesium milk, etc.


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