Introduction to Prepare Colloidal Solution of Egg Albumin
We will be learning about the procedure to experiment on this page. This experiment will help us prepare a colloidal solution of egg albumin. Before getting started, let us look at what a colloid solution/mixture is in Chemistry.
Colloidal Solutions
Colloidal Solutions, known as Colloids, are mixtures where, when looked at microscopically, there is a suspension of highly tiny insoluble particles in another substance.
We cannot assume all mixtures to be colloidal. The mixtures where suspended particles do not settle down at the bottom but still get evenly dispersed into another substance can be known as colloids.
We can Classify these Sols Into Two Different Types
Lyophobic Sols: These are 'liquid hating' sols that get very little or no interaction with the dispersed phase and the dispersion medium. The dispersed phase in this sol has a slight affinity for the dispersion medium.
Lyophilic Sols: These are the 'liquid loving' sols that attract solvents. Here, the colloidal solution firmly attaches to the dispersed medium and phase.
In the case of the egg albumin that is obtained from eggs, these albumins form a lyophilic sol with cold water. This sol is not affected by any traces of impurities and is stable.
Now, after learning about this concept, let us proceed with the actual procedure in theory:
Aim
The aim is to prepare a colloidal solution (lyophilic sol) of egg albumin
Theory
Lyophilic sol is obtainable from the egg albumin present in the eggs. When we mix the egg's albumin with cold water, we obtain lyophilic sol.
This sol is stable and generally not affected by its impurities.
Egg Albumin's formula is C16H26O5.
Required Apparatus Includes
Beakers (250 ml and 50 ml)
Glass rod
Funnel
Filter paper
Tripod stand
Burner
Distilled water
Wire gauze
Soluble starch (500 ml)
pestle and mortar
Porcelain dish
Procedure
The first step is to break down the outer shell of the particular egg with the help of the glass rod from our Apparatus.
Color the colorless liquid (albumin water) and the yellow part and decant the colorless liquid into another beaker.
In the beaker of 250mL, prepare 100mL of the NaCl solution of 5% (w/v).
Pipette on the albumin and start pouring it into the beaker that contains sodium chloride solution. Mix this by constantly stirring for 15 to 20 minutes, ensuring that the sol is prepared well and egg albumins in water forms.
Hence, filter the contents of the beaker with the help of filter paper, a funnel, and a label to filtrate as much as possible.
Precautions
The Apparatus should be adequately cleaned for conducting these experiments.
Now separate the egg albumin water and the yellow yolk before mixing it with sodium chloride solution.
After this, we have to stir the mixture constantly in the beaker and also add the egg albumin to prepare our egg albumin sol.
We will have to make sure that the preparation of egg albumin sol is done at room temperature because the precipitation of the egg albumin will take place in a hot solution.
We should use distilled water to prepare the egg albumin sol. (Colloid is formed in the water when there is a presence of Egg albumin in it)
More About the Colloidal Solution of Egg Albumin
In this article, we will discuss the procedure to perform an experiment that will help us understand how to prepare a colloidal solution of Egg albumin. Before starting the experiment let’s first understand What is a colloid mixture or colloidal solution in Chemistry?
Colloidal solutions or Colloids are the mixtures in which microscopically insoluble particles of one substance are suspended in another substance. Not all the mixtures are colloids. The mixture where suspended particles don’t settle down at the bottom but get evenly dispersed into another substance. The size of the colloids ranges from 1 nm to 1000 nm. One important class of colloidal systems is sols. In sols, the dispersed phase is a solid medium, and the dispersion medium is liquid in the state, and depending upon the nature of the interaction between the dispersed phase and dispersion medium sols can be broadly classified into two types.
Lyophilic Sols: The term lyophilic means ‘liquid-loving’ or ‘solvent- attracting’, which means in this colloidal solution there is a strong affinity towards the dispersed phase and the dispersion medium.
Lyophobic sols: The term lyophobic means ‘liquid-hating’, which means in these sols, there is little or no interaction between the dispersed phase and the dispersion medium i.e., a dispersed phase has little affinity for dispersion medium.
Egg albumin obtained from eggs form a lyophilic sol with cold water. The sol is stable in nature and not affected by the presence of traces of impurities. Now let’s discuss the procedure.
Additional Information
The standard method we can classify a colloid is based on the phase at which our substance disperses and our dispersion medium. Some colloids are emulsion, sol, gel, foam, and aerosol.
Sol is a colloidal system. In this system, the dispersed phase is solid, whereas the dispersed medium is liquid—for example, Paint, Mud, Blood, Ink.
An emulsion can be defined as a colloidal system in which the dispersion phase is liquid. The dispersion medium is also a liquid—for example, Salad Dressing, Brewed Coffee, Milk.
Foam is another type of colloidal system where we observe that the dispersed phase is gas, and the dispersion medium is solid or liquid—for example, Whipped Cream, Bubble Bath, Fire Retardant.
Aerosol is a colloidal system with the dispersed phase being a liquid or solid. The dispersion medium is gas—for example, Perfume, Hairspray, Mist, Fog.
The gel is a colloidal system with a solid dispersion phase and a liquid dispersion medium—for example, Cheese, Jam, Rubber, Gelatin, Toothpaste.
FAQs on To Prepare Colloidal Solution of Egg Albumin
1. What exactly is a colloidal solution of egg albumin?
A colloidal solution of egg albumin is a type of lyophilic sol. In this solution, the large protein molecules from egg white (albumin) act as the dispersed phase, and they are spread throughout water, which is the dispersion medium. Because the protein has a strong attraction to water, it forms a stable solution.
2. How is a colloidal solution of egg albumin typically prepared?
To prepare this sol, the colourless part of an egg (albumen) is first separated from the yolk. About 50 mL of distilled water is taken in a beaker and heated to around 50-60°C. The egg albumin is then added drop by drop to the warm water while stirring constantly. This process ensures the protein molecules disperse evenly to form a translucent colloidal solution.
3. What is the main difference between albumin and albumen?
Although they sound similar, albumen refers to the entire egg white itself, which is a mixture of protein and water. Albumin, on the other hand, is the specific name for the main group of proteins found within the egg white. In simple terms, albumin is the key ingredient that makes up the albumen.
4. How does a lyophilic sol, like egg albumin, differ from a lyophobic sol?
The main difference lies in the interaction between the dispersed phase and the dispersion medium.
- In a lyophilic (solvent-loving) sol, like egg albumin in water, there is a strong attraction between the particles and the solvent, making them stable and easy to form.
- In a lyophobic (solvent-hating) sol, such as a solution of metal sulphides, there is very little attraction. These sols are less stable and require special methods to prepare.
5. Why is the mixture of egg albumin and water called a lyophilic sol?
It is called a lyophilic (or 'solvent-loving') sol because the large albumin protein molecules have a strong affinity for water molecules. This natural attraction allows them to be easily dispersed and remain stable in the solution without settling down, which is a key characteristic of lyophilic colloids.
6. How does cooking an egg demonstrate a key property of colloids?
Cooking an egg is a perfect example of coagulation. When you heat the liquid egg white, the albumin sol is destabilised. The heat causes the protein molecules to unfold (denature) and clump together, forming a solid, opaque white mass. This change from a liquid sol to a solid is a fundamental property of many colloidal solutions.
7. What would happen if a small amount of salt (an electrolyte) is added to the egg albumin sol?
Adding an electrolyte like salt would likely cause the sol to coagulate or precipitate. The ions from the salt would neutralise the electrical charges on the surface of the albumin protein molecules. This removes the repulsion between them, allowing them to stick together and settle out of the solution, thus destroying the colloid.
8. What are some methods used to purify a freshly prepared colloidal solution?
Colloidal solutions often contain impurities like electrolytes. To purify them, methods are used that separate particles based on size. Common techniques include:
- Dialysis: Using a semi-permeable membrane to allow small impurity ions to pass out while retaining the larger colloid particles.
- Electrodialysis: A faster version of dialysis that uses an electric field to speed up the removal of ionic impurities.
- Ultrafiltration: Using special filter papers with extremely fine pores to separate the colloid particles from the solvent and smaller solutes.
