Dispersed Phase

What is Dispersed Phase?

A liquid that is suspended in the form of fine droplets in a continuous phase.

We have classified colloids on the basis of the dispersed phase and the dispersion medium into categories such as solid sol, sol, aerosol, emulsion, gel, foam, etc. and also in the basis of the nature of the interaction between the dispersion medium and the dispersed phase into lyophilic and lyophobic colloids.

Size of the Molecules of the Dispersed Phase

Size of the Molecules of the Dispersed Phase

In this section, we will choose another basis of classification of the colloids, that is, the type of particles of the dispersed phase.

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On the basis of the types of particles in the dispersed phase, colloids can be classified into the following types:

  1. Multimolecular colloids
  2. Macromolecular colloids
  3. Associated colloids

1. Multimolecular Colloids

When the dissolution of smaller molecules of a substance or many atoms takes place, they combine to form a species whose size is in the range of colloidal size. The species formed is known as the multimolecular colloid.

For example, Sulphur solution contains particles that have thousands of S8 molecules.

2. Macromolecular Colloids

In this type of colloids, the macromolecules from a solution with a suitable solvent. The size of the particles in the macromolecular solution lies in the range of colloidal particle size. Thus, this solution is also known as the macromolecular colloid. The colloid formed here is similar to that of the actual solution in many respects and is very stable.

Example: Starch, proteins, enzymes, and cellulose are the naturally occurring macromolecular colloids whereas polyethylene, synthetic rubber, etc. are the synthetic macromolecules.

3. Associated Colloids

Some substances act as strong electrolytes when they are in low concentrations, but they act as colloidal solutions when they are in high concentration. In higher concentrations, particles aggregate showing colloidal behaviour. These aggregated particles are known as micelles. They are also known as the associated colloids. The formation of the micelles occurs above a particular temperature called the Kraft temperature (Tk) and also above a specific concentration called the critical micelle concentration. These colloids can be reverted by diluting them.

Examples of some associated colloids are soaps and synthetic detergents.


1. What is dispersed medium?
A distributed medium consists of two non mixing media. This includes, more precisely, isolated elements of one medium that are scattered in a continuous second medium. The two media can be very distinct in nature. They can particularly be a gas, a liquid or a solid.

2. What is dispersed medium and dispersed phase?
The phase that is dispersed or present in colloidal particle shape is called the dispersed phase. The medium the colloidal particles are distributed in is called the medium of dispersion. Example: Starch represents the dispersed phase in a starch solution, while water is the dispersing medium.

3. What is dispersed phase in colloid?
Two of the three main forms of mixtures is a colloid with the other two being a solution and a suspension. One material in colloids is uniformly distributed within another. The dispersed material is referred to as being in the dispersed phase, while the material in which it is distributed is in the continuous phase.

4. Is blood a colloid?
Colloids contain larger insoluble proteins, such as gelatin; a colloid is blood itself.

5. What is a true solution?
True Solution is a homogeneous mixture of two or more substances in which dissolved material (solute) has the particle size of less than 10-9 m or 1 nm in solvent. An example of a true solution is a simple solution of sugar in water.

To learn more about the classification of colloids based on the types of particles and other related topics, download BYJU’S – The Learning App.

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