All the gems and juices you can see in the image above are colloids. Have you felt water droplets in the fog? Yeah! Fog is also an example of a colloid. In fog, water molecules are dispersed in the gas. In the same way, you must have observed many such examples of colloids in your daily life.
So, this article will discuss what colloids are, the properties of colloids and applications of colloids.
What are Colloids?
In chemistry, colloids are heterogeneous mixtures of two substances in which minute particles of one substance are dispersed in another substance. The substance whose minute particles are suspended in another substance is called the dispersed phase, while the substance in which it is suspended is called dispersion medium. For example, in the fog dispersed phase is water (liquid) and dispersion medium is different gasses. We can’t see particles of a dispersed phase in colloids by naked eyes as they are very small in size.
Examples of Colloids
We see many colloidal solutions around us. Many food items such as cake, milk, bread, butter, ice cream, fruit juices, whipped cream etc. are examples of colloids. Apart from these, fog, mist, clay etc., are also examples of colloids. We are providing a list of examples of colloids with their dispersed phase and dispersing medium below –
Properties of Colloids
Colloids show the following properties.
It is a heterogeneous mixture.
The size of colloidal particles is very small. Their particle size ranges between 1-1000 nanometers.
It shows the Tyndall effect. It means it scatters the beam of light and shows its path through itself.
They don’t settle down when left undisturbed for some time. It means colloidal solutions are quite stable.
They cannot be separated by the filtration process.
They can be separated by centrifugation.
Colloidal particles show Brownian movement.
Applications of Colloids
Colloids have various applications in many fields. Some uses of colloids are listed below –
Colloids are used in the foods and food industries at a large level. Many foods which we consume are actually colloidal in nature. Such as milk, cheese etc.
Colloids have various applications in the medicinal field as well. Many medicines which we use are in the form of emulsions. Antibiotics such as penicillin and streptomycin are given in the form of colloidal solutions so that they can be absorbed by the human body easily.
Colloids are used in water purification.
Sewage water contains impurities like dirt, stool, urine etc. which are dispersed in water. Thus, it forms a colloidal system. These can be removed by electrophoresis.
Smoke is also a colloidal system of carbon particles in the air. This can also be purified by electrophoresis.
These are used in artificial rain as well.
Rubber is obtained by a colloidal solution called latex through coagulation.
Treatment of the skin of animals to get leather is called tanning. In the process of tanning, colloids are used.
Micelles formed in the cleansing action of soaps are colloids.
Colloids are used in the form of smoke in smoke screens to hide some things in the military.
The blue color of the sky is due to a colloidal property shown by the sky. Dust particles dispersed in the air scatter sunlight.
Many nanomaterials are prepared by colloids.
These are used in metallurgy during froth floatation.
These are used in the treatment of hypovolaemic patients.
A silver colloid is used as a germicidal agent.
Many colloids are used as anticancer drugs, such as copper colloids.
Colloids are used in the preparation of anti-syphilis antibodies.
Proteins are colloids and are used in various ways.
These are used for targeted drug delivery.
These are used as cosmetic ingredients for many cosmetic products.
These are used as fungicides and pesticides.
These are used in plastic surgery of many body parts.
These are used in dentistry.
These are used in wound dressing materials as well.
This was brief on colloids with emphasis on their applications; if you want to get detailed study notes on the topic colloids, then register yourself on Vedantu or download the Vedantu learning app for Class 6-10 IIT JEE and NEET.
FAQs on Applications of Colloids
1. What exactly is a colloid, and how is it different from a true solution?
A colloid is a mixture where one substance of microscopically dispersed insoluble particles is suspended throughout another substance. The main difference from a true solution lies in the particle size. In colloids, particles are larger (1-1000 nm) and can scatter light (the Tyndall effect), whereas in true solutions, particles are much smaller and do not scatter light.
2. What are some common examples of colloids we use in our daily lives?
Many everyday items are colloids. Some common examples include:
- Food products: Milk, butter, cheese, jelly, and ice cream.
- Household items: Paint, ink, and toothpaste.
- Natural phenomena: Fog, mist, and clouds.
3. How are colloids important in the medical and pharmaceutical fields?
Colloids are essential in medicine because their large surface area allows for easy assimilation by the body. For example, Argyrol (a silver sol) is used as an eye lotion. Milk of Magnesia, an antacid, is a colloidal suspension. Many injections, like those containing colloidal gold or calcium, are used to deliver nutrients or treatments effectively.
4. How does the cleansing action of soap depend on colloid formation?
The cleansing action of soap is a direct application of colloid chemistry. Soap molecules form aggregates called micelles when mixed with water. These micelles are colloidal in size. The oily dirt particles get trapped inside the core of the micelles, which can then be easily rinsed away with water, effectively cleaning the surface.
5. Why don't the particles in a colloid settle down due to gravity?
Colloidal particles remain suspended and do not settle for two main reasons. First, they are in a state of continuous, random motion called Brownian motion, which counters gravity. Second, all particles in a colloid carry the same electrical charge (either positive or negative), causing them to repel each other and preventing them from clumping together and settling.
6. How do water purifiers use the properties of colloids to provide clean water?
Natural water often contains suspended impurities like clay and mud, which are colloidal in nature and carry a negative charge. To purify it, a substance like alum is added. The positively charged ions from alum neutralise the charge on the colloidal impurities. This process, called coagulation, causes the particles to clump together, become heavy, and settle down, making the water clear.
7. Can you explain how the formation of a river delta is an application of colloids?
Yes, delta formation is a natural example of colloid coagulation. River water is a colloidal solution containing negatively charged clay and sand particles. When the river flows into the sea, the seawater, which contains many electrolytes (salts), neutralises the charge on these particles. This causes them to coagulate and deposit at the point of contact, gradually forming a delta over time.
8. What is the industrial importance of colloids in processes like rubber manufacturing?
Colloids are vital in many industries. In rubber manufacturing, for instance, latex is a colloidal solution of negatively charged rubber particles. The rubber is obtained by coagulating this latex, often by adding an acid. This process is also fundamental in other industries like tanning leather, paint production, and cement manufacturing.
