Chemistry has taught us that there are a variety of substances around us, and many of them exist in pure forms, while some exist in mixtures. What’s more fascinating is that the mixtures are present in different types and forms that may or may not be visible in our eyes.
Because of different mixtures present, there are different methods of separation types as well. Let us dig deeper into what exactly separation means and the various methods of separation.
What is the separation of mixtures, and why do we do it?
The removal of some element or impurities from a mixture is called the separation of mixtures. The separation of the mixture is done to remove the impurities from the pure substance or get a useful material from any mixture of substances. The method of separation applies to a mixture depending on the composition and types of the mixture.
Types of Mixtures
There are two types of mixtures that are present summarised as:
- Homogeneous mixtures that are not visible under the naked eye, like Air, Sea Water, detergent, Salt/Sugar water, etc.
- Heterogeneous Mixtures visible from the naked eye like sand, oil and water, pebbles in rice or dal, mixture, etc.
Methods of Separation
The separation techniques used on different substances are different based on the physical and chemical properties of the substance in the mixtures. Sometimes, it also happens that there might be a need for 2 or more processes required to separate the mixture containing different elements of different properties. Some of the most prevalent separating methods are:
- Sedimentation and Decantation: Do you know how the people of earlier times filtered the pure water from the impure water? The answer is through the process of sedimentation and decantation. This process is done when the mixtures are insoluble and also vary in density. This process involves 2 steps in total:
- Sedimentation: This is a process in which we leave the mixtures undisturbed for some time to let the heavier density materials settle down at the bottom of the container. The impurities that settle down at the bottom of the container are known as sediments.
- Decantation: When the impurities in the mixture are settled down, the top layer of the mixture is removed into another container, leaving the sediments in the previous container.
Application of sedimentation and decantation: When the mixture of sand and water is left undisturbed for some time, the sand gets collected at the bottom of the container, leaving pure water on the top that can be later removed to another container.
Application of sedimentation and decantation separation process: This process is used in the water purification process at a large scale.
You may well know the famous Dandi March by Mahatma Gandhi. In the Dandi march, they have produced salt from the seawater through the process of evaporation. The process of evaporation works when the mixture is a mixture of soluble and solvent.
In seawater, salt is the soluble substance, and water is the solvent. The seawater or the mixture is heated or left under the sun to evaporate the solvent into gas, leaving the soluble residue behind.
Application of Evaporation separation process: This process is used widely to manufacture salt.
- Magnetic Separation:
Magnetic separation is a process of separation used when one of the mixture’s components is magnetic—for example, the mixture of iron filings and impurities.
In this process, the magnetic and non-magnetic substance mixture is passed through a magnetic roller or, if the quantity is less, a magnet hovers upon the mixture. The magnetic substance is filtered out from the magnet, and the non-magnetic elements are left as a residue.
Application of Magnetic separation process: This method is widely used in the water purification process.
When the mixture has substances of different densities but is mixed so that they cannot be separated by sedimentation, they can be separated by applying a centrifugal force from a device called a centrifuge by the process of centrifugation.
In this process, a spinning force called centrifugal force separates the mixtures of varied density. The substance with lower density comes on the top, and the substance with higher density settles at the bottom that is removed later.
Application of centrifugation separation process: This process helps make butter, purify virus particles, etc.
The distillation process is used when the mixture contains two soluble liquids with considerable differences in their boiling points. The distillation process requires an apparatus that contains 2 beakers, a condenser, a thermometer, and a bunsen burner.
The liquid mixture is boiled until the boiling point of one liquid, which then evaporates and passes through the condenser. In the condenser, the liquid cools down and gets collected in a separate beaker.
Application of distillation separation process: It helps in the purification of acetone from water and the distillation of alcohol.
There are various other examples of separation techniques that we encounter in daily life. If we process it carefully, we will be able to differentiate the maximum number of processes associated with the separation techniques. You will be able to figure out the mixture’s components based on their visibility, density, colour, shape, size, etc. You will also be able to figure out the different methods of separation types.
Moreover, you will be able to separate the heterogeneous mixtures which can be seen by the naked eye and the homogeneous mixtures that play hide and seek with our eyes. It depends on your ability and skill to identify which type of mixture is available to you and which will be the best technique to separate the impurities from the pure substance. Whether in an exam or day-to-day life, contemplate the properties and then provide the best suitable technique to obtain a pure substance.