Dhristi JEE 2022-24

What is the Dispersed Phase?

To understand the dispersed phase, we need to understand what a colloid is. A colloid is a heterogeneous solution. In this solution, a dispersed phase is suspended in the dispersed medium. That is, the particles of the dispersed phase are present in the particles of the dispersed medium. A colloid solution does not possess a uniform mixture.

Water in starch or water in ink is an example of a heterogeneous mixture. Water is considered a dispersed medium in the above criteria, and starch or ink can be regarded as a dispersed phase. Two phases exist in this case. One step possesses finely differentiated particles suspended in a continuous medium. The stage with finely differentiated particles is called the dispersed phase. A dispersed medium consists of two media that do not mix. These two media can be different in properties altogether. Precisely, they can be a liquid, a solid or a gas. There are various everyday life examples of dispersed media. Milk, which we most probably use daily, is made up of oil drops dispersed in water. Shaving creams contain tiny airdrops of water dispersed in the air.


Difference Between Dispersed Phase and Dispersed Medium

The dispersed phase of dispersion is the discontinuous phase that distributes throughout the dispersion medium. It is one of the two stages of a colloid. The dispersion medium is the continuous phase of a colloid, and it distributes throughout the dispersion medium. The dispersed phase is known as the internal phase, whereas the dispersion medium is called the external phase. Examples of the dispersed phase include dust in the air, whereas that of dispersion medium includes water in milk.


Types of Dispersion Systems

There are two types of dispersion systems, Molecular Dispersions and Coarse Dispersions. Molecular dispersions are dedicated solutions to a solute phase in the solvent. The dispersed phase is homogeneously distributed in the dispersion medium. Examples of molecular dispersion are air (consisting of various gasses like nitrogen and oxygen), electrolytes, and alloys.

The second type of dispersion medium is of the coarse kind. These are heterogeneous dispersed systems. Fast sedimentation of the dispersed phase is observed owing to the coarse dispersions, mainly due to gravity.


Dispersed Phase: Classification and Types

Based on the type of dispersed phase, colloids can be classified into various types. These include sol, emulsion, foam, and aerosol. A colloidal suspension of solid particles in a liquid is called a sol, e.g., Ruby glass. An emulsion is a colloidal suspension of two drinks, e.g., milk. Foam is formed when gas particles get trapped in a liquid or solid, e.g., soap in water. Aerosols are small particles of liquid or solid dispersed in a gas, e.g., smoke, fog, mist, etc.

Depending upon the minute particles' nature of the dispersed phase, the colloids are mainly differentiated into three types:

  • Multimolecular colloids

  • Macromolecular Colloids

  • Associated Colloids


Multimolecular Colloids

When a substance gets dissolved in a dispersion medium, it gets separated into several smaller molecules of different sizes. Usually, their size varies from 1-1000nm. After the separation of the particles, the colloid constitutes several atoms and molecules known as multimolecular colloids.

Example: Hundreds of Sulfur molecules are held together by van der Waals force and form Sulfur Solution.


Macromolecular Colloids

Its size is relatively more. However, in a suitable solvent, these form solutions whose size may or may not remain in the colloidal range. This arrangement is popular as Macromolecular Colloids.

Example: Enzymes, cellulose, and proteins are naturally formed macromolecular colloids, but rubber and polythene are synthesized.


Associated Colloids

Basically, these are behaving like strong electrolytes. However, when a suitable condition like in higher concentration, they show the behavior of colloidal particles. Because of this nature, these are known as Associated Colloids and also famous as a micelle.

Examples: Soaps and detergents 


How Does Dispersion Occur?

The agglomerated particles get separated from each other. A new line of interaction between the dispersion medium's inner surface and the outer surface of dispersed particles is created. This whole process is aided by molecular diffusion and convection. Through molecular diffusion phenomena, dispersion occurs through different concentrations of the media introduced throughout the bulk medium. The difference in engagement between dispersed material and the bulk medium creates a concentration gradient that drives the medium's dispersion. 

This results in an equal dispersion of particles in the medium. In convection, variation in velocity between paths of flow in the bulk medium facilitates the equal distribution of dispersed material in the medium. Diffusion is the primary mechanism in dispersion, although it is driven by convection in some cases. In most cases, convection is what helps in accelerating the process of diffusion.


How Does Dispersion Occur in Prism?

To understand how dispersion occurs in a prism we need to first understand what is a prism. A prism is two rectangular bases and three rectangular surfaces in a solid figure. The angle of the prism is the angle between each surface. The surfaces are parallel and equal. Now let's begin with the experiment. 

We need a constant beam of light, a prism, and a white plain wall to produce seven different colors with a single white light. First, place the project components near the window. Make sure that the sunlight should fall on the prism in such a way that it should cover one side of the prism and then on the wall. 


Observation

You can observe that a single beam of light from the sun is now separated into seven different colors. This process of separating a single light into various wavelengths is known as dispersion of light. 

The colors that you see are called VIBGYOR. VIBGYOR stands for letter V as Violet, the letter I as indigo, letter B as blue, letter G as green, letter Y as yellow, letter O as Orange, and letter R as red.  The color pattern which we get after throwing a single beam of light on a prism or any other object is called a spectrum. Another example of the spectrum is the rainbow but you cannot see all the seven colors because the colors overlap each other.


What is a Dispersion System and How Does it Work?

The dispersion system has a two-sided system that is made up of microscopic particles along with a medium that helps them to be suspended. The dispersion system works on a basic principle that it separates the collection of particles from each other. Light can be a common example of dispersion. The second commonly used example is a rainbow. Let us know how this works. The speed of the light ray results in light dispersion. Similarly, the dispersion of a rainbow is a spatial disconnection of a single white light into many different lights.


Dispersion Medium

  • Foam

Foam is a colloidal system. The particles are gas bubbles whereas the medium is a liquid. Foam can be easily classified as something which is light in weight or rigid form. Long-lasting foams are made from liquid foams, purposely made for heavy usage. For example - Fire fighting. Stabilizers are used to prevent the coalescence of the bubbles. Proteins are well known as a stabilizer as they are edible in nature.

  • Aerosol

It is described as the chemistry of solid, liquid, and gas particles. Fog is a natural aerosol.

  • Solid suspension

A solid suspension is a mixture in which the solute particles do not dissolve. The mixture of chalk water is a common example of a solid suspension.

  • Gels

Gels are solid in the medium. Gelation is the process in which gel is foamed.

  • Colloidal Suspension

The particle size of a colloidal suspension is large. Muddy water is a good example of colloidal suspension. 

  • Emulsion

The emulsion is a mixture of more than one liquid or moire that cannot be mixed. Emulsion belongs to the general class. A golden example of an emulsion is water and oil. If stirred it will mix for a while but soon it will be separated. 

  • Solid Foam

Dry wood is a classic example of solid foam. they are made out of a specific framework. Commonly used in yoga mats.


What is a Colloid?

A colloid is a mixture of only one particular substance which is evenly distributed. There can be only two different states. Diameters range between 5 and 200 nanometres. Milk is a classic example of colloid in liquid whereas shaving cream is a colloid of gas inside the liquid.


What is a Solution in Chemistry?

The solution is a similar mixture of two or more substances in equal amounts. However, Solutions of gas and solid are possible. A commonly used example is air. Air is a mixture of several gases but the major gases of air are oxygen and nitrogen. The solution consists of two substances, Solvent, and the substance mixed with it is called the solute. 

  • Solvent

The solvent is basically a liquid in which various materials can be mixed to make a solution. For better understanding, water is a solvent. 

  • Solute 

The solute can be a substance or a material that has been dissolved in a solvent to create a mixture. A common example is a saltwater. In this case, salt is a solute mixed with water, water is solvent to produce a mixture called a solution.


Conclusion

We have covered all aspects of the Dispersed Phase and its classification. This clear picture will help you in learning the topic well.

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FAQs (Frequently Asked Questions)

1. What is a Colloid, and How does it Differ from a Solution?

A colloid is a substance in which minute, microscopically dispersed insoluble particles of one substance are suspended in another substance. The size of colloidal particles varies from 1-1000 nanometers. We will study more about colloids in another column. A solution exists in a single phase only, and no visual interface exists. Whereas in a colloid, two different phases, namely the dispersed phase and dispersion medium, exist. An interface between them can be observed. You can download the PDF format of this information from the Vedantu website.

2. Can We Distinguish Between the Dispersed Phase and the Dispersed Medium?

Yes, we can distinguish between the dispersed phase and the dispersed medium. On adding dispersion medium, emulsions can be diluted to any extent. The dispersed phase forms a separate layer if added in excess. There are various advanced techniques of separation of the dispersed phase and dispersion medium. One such method is micro-filtration. In colloids, both the stages cannot be separated by simple filtration but can be separated using centrifugation. For example, butter is separated from cream by centrifugation.

3. What are the Types of Dispersion Medium?

The three types of dispersion medium are solid, liquid and gas. The colloids are classified according to the interaction between the dispersed phase and dispersion medium. The dispersion mediums are again characterized owing to their interactions with the dispersed medium. However, depending upon the phase of dispersion, Colloidal Dispersion can be separated further into eight types such as:


Mentioned below are 8 types of dispersion medium.

  • Foam

  • Liquid Aerosol

  • Solid suspension

  • Gels

  • Colloidal Suspension

  • Liquid Aerosol

  • Emulsions

  • Sold foam

4. What is a mixture?

In simple words, a mixture made when two or more two substances are mixed but not on chemical levels is called a mixture. As it is not chemically mixed, separation is easy. Substances in a mixture do not lose their natural properties. However, the amount of proportion is not fixed. 


Mixtures can be further classified into two groups that are: Heterogeneous and homogeneous mixtures. In Heterogeneous mixtures, substances are not equally spread. Whereas, Inhomogeneous mixtures, all the substances are evenly distributed.

5. What are solvent and solute?

The solvent is basically in a liquid state. The solvent is something in which substances are dissolved to make a mixture out of it. The most common example is water. Solvents are well known for their ability to dissolve any substance mixed in them. On the other hand, a solute is a substance that is dissolved in a solvent to create a mixture. If compared, the proportion of solvent is always greater than the proportion of solute. The classic example of solute can be salt.

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