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
In this section, we will choose another basis of classification of the colloids, that is, the type of particles of the dispersed phase.
On the basis of the types of particles in the dispersed phase, colloids can be classified into the following types:
- Multimolecular colloids
- Macromolecular colloids
- 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 form 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 concentrations. 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.
Frequently Asked Questions – FAQs
What is dispersed medium?
Two media that do not combine consist of a distributed medium. More precisely, it comprises one medium’s isolated elements which are scattered in a second continuous medium. Both media can be very distinct in essence. They may be a gas, a liquid, or a solid in particular.
What is the dispersing medium in a colloid?
A colloid is a heterogeneous aggregate that has an intermediate particle size between those of a solution and a suspension. Throughout the dispersion medium, which can be a metal, liquid , or gas, the scattered particles are distributed uniformly.
What are dispersed systems?
A dispersion is a mechanism in which, in a continuous phase of another substance, scattered particles of one material are dispersed. Particle dispersions too broad for sedimentation are commonly referred to as suspensions, while those with smaller particles are referred to as colloids and solutions.
What are 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 is called the medium of dispersion. Example: Starch represents the dispersed phase in a starch solution, while water is the dispersing medium.
What does colloidal mean?
A mixture in which very tiny particles of one substance are evenly distributed across another substance. In addition, the particles are bigger than the ones in a solution and smaller than the ones in a suspension. Colloids include ink, milk, and fog.
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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