Since the past few years, research in the field of science has led to many important discoveries being made in the areas related to physics, astrophysics, chemistry, and particles that make up our world, and everything around us.
With the recent findings in chemistry, the nature and structure of atoms, physics, etc. scientists have come to know a lot about the physical and chemical ways that compounds mix with each other and have also come to know about various techniques like paper chromatography, that can be used to separate some compounds that were mixed physically.
There are various ways that two or more substances can be mixed together, depending upon the nature of the substances, and the mixing techniques.
Generally, the most common form of mixing is seen in a physical process that involves the dissolution of one substance with another physically. In this case, there are three important terms to know about; solute, solvent, and solution.
WHAT IS A SOLVENT
When two substances are mixed physically, there is generally a liquid in which another substance is dissolved. This liquid or gas or in some cases a solid is known as a solvent. Basically, a solvent is a substance that does not undergo any phase transformation once the mixing process is over.
For example, if a solid like salt or sugar is dissolved in water, then water in this case is a solvent. In this case, the solvent that is water, as well as the final solution that we get, is a liquid.
WHAT IS A SOLUTE
A solute is a substance that dissolves or mixes with another is known as solute. It may or may not undergo a phase transformation. For example in the case of salt and water, salt is the solute that is solid. When dissolved, it disappears into the solution and we cannot make out its earlier phase that was a solid as we observe the final solution.
In the typical example of a solid solute and a liquid solvent, the molecules of the solute adjust themselves in the space between the molecules of the solvent to form the final solution. Chemically, not much has changed but it is impossible to separate the solid solute from the solution after it is formed.
In the case of liquid solute and liquid solvent, there is no proper way to know the difference between these two terms, and separating two constituent liquids from the final solution requires special skills and processes like paper chromatography to be used.
WHAT IS A SOLUTION
The final product that is formed after mixing a solute and a solvent is a solution. The solution is of the same physical state or phase as the solvent used. If the solvent is a gas, the solution will be a gas and the same for the case of a liquid or a solid solvent.
Depending upon the physical state of the solute and solvent, we have various types of solutions:
- Solid solute and solid solvent: examples are alloys like brass with zinc in copper
- Solid solute and liquid solvent: examples are salt in water or sugar in water
- Liquid solute and solid solvent: an example is mercury in silver
- Liquid solute and liquid solvent: an example is a mixture of alcohol and water
- Liquid solute and gaseous solvent: an example is water drops in air
- Gaseous solute and solid solvent: an example is hydrogen on the surface of metals
- Gaseous solute and liquid solvent: an example is carbon dioxide in water
- Gaseous solute and gaseous solvent: an example is a mixture of oxygen and nitrogen in the air
COLLOIDAL SOLUTIONS
In some examples of solute and solvent mixing together, sometimes, the solid solute particles remain suspended in the solvent and do not dissolve. This is a middle state in which neither the solid dissolves and disappears and nor the solid settles down in the liquid which mostly happens if chemically, the solute cannot be dissolved in the solvent.
These solutions are called colloidal solutions and it has also been found that the reason that solute particles remain suspended in the colloidal solution is due to the presence of charge.
Somehow, the solute particles when mixed with specific solvents acquire a slight amount of charge on them and this charge keeps them repelling from the other solute particles and that results in the forever suspension of these particles in the solution.
Tyndall effect is seen in colloidal solutions that is the phenomenon of scattering of light through the solution due to suspended solute particles. Some examples of colloidal solutions are fog, smoke, milk, and mayonnaise, smoke in water, etc.
