Dispersed Phase and Dispersion Medium - Definition, Examples and FAQs

Before briefly discussing the dispersion phase and dispersion medium, let us discuss colloids.
There exist three types of mixtures- solution, suspension, and colloid.

What is dispersed phase and dispersion medium?

A medium in which the colloidal particles are dispersed is known as dispersion medium. A particle range of 1-1000 nm in diameter is present in a colloidal suspension. They can also be termed colloidal dispersions as the substances fail to settle at the bottom of the vessel. Colloidal particles have enormous surface area per unit mass which is a characteristic feature of colloids. The colloidal solution comprises the dispersed phase and the dispersion medium.

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Define the term Phase:

Physically and a chemically consistent or homogeneous portion of the entity that can be segregated mechanically from a non-homogenous entity and that could include an individual or a combination of substances. One must not be confused between phase and states of matter as they both are different and there can be varied immiscible phases of the identical states of matter.

Matter can prevail in various phases yet continue to remain in the same state of matter. If we consider an example of a liquid mixture. It exists in oil and aqueous phases.

Equilibrium states can also be illustrated with the help of phases using a phase diagram.

Phase examples:-

The various phases used to depict the states of matter are as follows-

• Solids

1. Definite shape and volume.
2. The vibration of particles is over fixed areas.

• Liquids

1. The absence of a definite shape but contains the definite volume.
2. Particles move independently but are still attracted to each other.

• Gases

1. The absence of definite shape as well as definite volume.
2. Random motion of the particles with fewer or no attractions between them.

• Plasma

1. Presence of no definite shape and volume
2. Presence of charge on particles.

• Bose-Einstein condensate

A state of matter is normally moulded when a boson gas of low density is cooled at a lesser temperature very close to absolute zero.

• Mesophases

Phases that are intermediate between liquid and solid.

Q. What are the dispersed phase and dispersion medium?

A phase that is in the shape of colloidal particles is called the dispersed phase.

The medium in which the distribution of colloidal particles that happen are called the dispersion medium.

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Dispersed phase & Dispersion medium-

Disperse meaning can be elaborated as a breakdown of particles in a certain direction. The dispersed phase contains finely divided substances or particles suspended in the continuous phase. The dispersion medium comprises two immiscible media provided they can be the same or different in physical properties. Specifically, they can be solid, liquid or gas.

Various everyday examples can be considered for a better understanding of the concept of the dispersed phase and the dispersion medium. For eg: Milk.

Now, what are the dispersed phase and the dispersion medium in milk?

The dispersed phase and the dispersion medium in milk is fat and water respectively. Both occur in a liquid state.

• Classification and types of the dispersed phase-

Classification of colloids is done into several types based on the types of the dispersed phase. They are-

1. Sol

Sol is a type of colloidal solution containing solid and liquid as the dispersed phase and the dispersion medium. Here, the solid particles are dispersed in a liquid medium or solution.

In simple words, sol is a solid dispersed in a liquid.

Eg: blood, ink, paint.

The dispersed phase and the dispersion medium in the blood is hormones, WBC’s, RBC’s, platelets and

Plasma.

Let us have a look at colloidal iron. The dispersed phase in colloidal iron is positively charged. When mixed with colloidal gold sol having a negatively charged dispersed phase, the charges get neutralized as mutual coagulation is influenced.

2. Aerosol

Liquid dispersed in a gas is called aerosol.

Aerosol is a colloidal mixture where the solid or liquid fractions are dispersed in the gaseous phase.

Hence, liquid dispersed in gas is termed an aerosol

Eg: cloud, smog, smoke.

3. Emulsion

The emulsion is a colloidal solution containing liquid as both the dispersed phase and the dispersion medium.

The emulsion can also be illustrated in the following way-

Small liquid droplets dispersed in another liquid is called emulsion.

Eg: milk, butter, cream.

4. Foam

Foam is a colloidal mixture having dispersed phase as a gas and liquid as the dispersion medium.

Here, dispersed phase in foam is called gas.

Eg: soap bubbles.

Hydrocolloid is a colloidal system when the dispersion medium used is water.

The dispersed phase and dispersion medium examples:

Colloids can also be classified based on the variety of particles in the dispersed phase. They are as follows-

1. Multimolecular colloids

The dissolution of small size particles of substance or several atoms results in the formation of new species having a particle size within the colloidal range.

Eg: the presence of numerous S8 molecules in sulfur solution.

2. Macromolecular colloids

The size is comparatively greater than multimolecular species. They form solutions of particle size that may or may not persist between the colloidal range.

Eg: enzymes, proteins, synthetic rubber.

3. Associated colloids

They exist as colloidal solutions at higher concentrations but behave as strong electrolytes at lower concentrations.

Eg: soaps, detergents, etc.

Difference between the dispersed phase and the dispersion medium/difference between dispersed phase and dispersion medium:

The dispersed segment of dispersion is the discontinuous segment that distributes all through the dispersion medium. It is one of the ranges of a colloid. The dispersion medium is the consecutive segment of a colloid, and it dispenses all through the dispersion medium. The dispersed segment is referred to as the inside phase, while the dispersion medium is known as the outside phase. Examples of the dispersed phase consist of dirt withinside the air, while that of dispersion medium consists of water in milk.

Also check-

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NCERT Chemistry Notes:

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• NCERT Notes For All Subjects