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Colloid Definition

Colloids are also referred to as colloidal solutions or systems. A colloid is a mixture of two or more components that are mixed physically rather than chemically. Colloids are mixtures in which minute, soluble particles of one substance are immersed in a different substance. Particles can be 0 to 1000 nanometers in size.

Colloid Definition

Dispersion Medium

The area of the colloidal solution where the particles are equally dispersed. For example, soda water includes gas and water; here dispersion medium is water.

Dispersed Phase

The phase that is uniformly spread across the colloidal solution is known as the dispersed phase. For example, soda water includes gas and water; here dispersed phase is gas.

Types of Colloids

1. Aerosol:

It is made up of liquid or solid particles suspended in a gas.

2. Emulsion:

The emulsion is a colloid formed by multiple liquids, one of which is a dispersion of another.

3. Foam:

It is made up of gas spread in a solid or liquid.

4. Sol:

It consists of tiny solid particles suspended in a liquid.

5. Gels:

Gels are colloidal solutions in which little liquid drops are dispersed across a solid dispersion medium.

Preparation of Colloids

1. Chemical methods:

Chemical processes such as double decomposition, oxidation, reduction, or hydrolysis can generate colloidal dispersions.

2. Electrical disintegration

It is used to create colloidal sols of metals like platinum, silver, and gold.

3. Peptization

Peptization converts precipitate into colloids by mixing some peptizing agents.

Uses of Colloids

  1. Colloids are frequently employed in research, health care, and daily life.
  2. Soup and halwa are a few foods that contain colloidal systems.
  3. Eye infections can be treated with colloidal silver, sometimes called Argyrols.
  4. Colloids are used widely in the medical field.
  5. Colloids are used to clean water.
  6. Colloids are also utilized to create fake rain.
  7. Rubber is produced by solidifying a colloidal fluid known as latex.
  8. The process of cleaning animal skin to produce leather is known as tanning. Colloids are utilized during tanning.
  9. In the military, colloids are utilized as smoke in smoke screens to hide various items.
  10. Anti-syphilis antibodies are produced using colloids.
  11. Colloids are used to prepare a lot of nanomaterials.
  12. They are used to treat people who are hypovolaemic.
  13. Colloids are utilized to deliver targeted drugs.
  14. Colloids are used during plastic surgery.
  15. Various commercial and natural goods contain colloids, such as whipped cream, cheese etc.
  16. Colloids are utilized as pesticides and fungicides.


1. Classification based on physical phase

There are eight types of colloidal systems based on whether the dispersed phase and the dispersion medium are liquids, solids, or gases. The examples of several types of colloidal and their popular names are listed below:

Sr.No Dispersed Phase Dispersion Medium Type of Colloid Examples
1 Gas Liquid Foam Whipped cream
2 Liquid Liquid Emulsion Milk
3 Solid Gas Aerosol Smoke, dust
4 Gas Solid Solid sol Foam Rubber
5 Liquid Solid Gel Cheese, butter
6 Solid Liquid Sol Paints
7 Liquid Gas Aerosol Fog, cloud
8 Solid Solid Solid sol Gem Stones

2. Classification based on interaction

Colloidal sols are categorized based on how the dispersed phase interacts with the dispersion medium.

1) Lyophilic colloids:

Lyophilic sols are colloidal sols created by mixing liquid with gum, starch, gelatin, rubber, etc.

2) Lyophobic colloids:

Colloids with a very low affinity for the dispersion medium are called lyophobic colloids.

FAQs on Colloids

1. Differentiate lyophobic colloids and lyophilic colloids.


Parameters Lyophobic Colloids Lyophilic Colloids
1. Materials It mostly consists of inorganic materials. It mostly consists of organic substances.
2. Preparation Require specialized preparation techniques and an electrolyte for stabilization. Easy to prepare by simply stirring, shaking, or heating the item with the dispersion medium.
3. Dispersion medium's affinity No affinity, solvent repelling High affinity, solvent attracting
4. Stability Unstable and quickly coagulated by electrolytes. Extremely stable and don't thicken when electrolytes are added.
5. Solvation Dispersed particles are not solvated. Dispersed particles are highly solvated.
6. Examples Metals, metal oxides, etc. Starch, protein, gelatin, gum, etc.

2. Define Colloids.


Colloids are mixtures of two substances in which microscopic particles are distributed and suspended over one another.

3. Specify the protection methods for lyophobic sol.


By including lyophilic sol, lyophobic sol can be protected.

4. List examples of colloids and specify the dispersed phase and dispersion medium.


1) Blood:

Dispersed phase:Albumin serves

Dispersion medium:Water

2) Cloud:

Dispersed phase:Water droplets

Dispersion medium:Air

3) Gold sol:

Dispersed phase:Gold particles

Dispersion medium:Water

4) Cheese:

Dispersion medium:water

Dispersed phase:Fat

5) Jelly:

Dispersing medium:Fruit pulp

Dispersed phase:Sugar syrup or water

6) Pumice stone:

Dispersion medium:Solid

Dispersed phase:Gas

List the four primary characteristics of colloids.


  1. It must be heterogeneous or generated by different elements, such as gold and water.
  2. Colloidal particles are incredibly small in size.
  3. It should be multi-phases like gas/liquid, solid / gas etc.
  4. The centrifugation method is utilized to separate colloid particles.

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