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As a child, you may have made suspensions using mud and water, flour and water, or tempera paint, which is a solid color suspension in water. These suspensions are heterogeneous mixtures of visible particles rather large. They’re foggy, and the dispersed particles settle out after mixing. When we make a solution, on the other hand, we make a homogenous mixture with no settling and molecules or ions as the dissolved species. Suspensions have very different behavior than solutions. The molecules or ions in a solution may be colored, but they are invisible and do not settle out when allowed to stand.
Colloid
A colloid is a mixture in which the particles are bigger than a molecule but smaller than those visible to the human eye. Colloid is one of three primary forms of mixes, with solutions and suspensions being the other two. The size of the particles that make up the three types of mixes distinguishes them. A solution’s particles are the size of molecules, measuring around 1 nanometer (1 billionth of a meter) in diameter. Those with more than 1,000 nanometers are used to produce suspensions. Finally, colloidal particles are measured in nanometers and vary in size from 1 to 1,000. Colloids are also known as colloidal dispersions because the particles that make up the combination are scattered or spread out.
Types of Colloids
Colloids are divided into two categories:
Multimolecular Colloids: Multimolecular colloids are formed when smaller molecules of material or several atoms dissolve and mix to produce a species in the colloidal size range.
Macromolecular Colloids: Macromolecular colloids are larger biomolecular colloids when submerged in an appropriate dispersion, such as enzymes or proteins. Rubber, cellulose, starch, and other materials are examples.
What are Colloidal Solution and their properties?
Brownian Motion: When an Ultramicroscope is used to view a sol, the suspended particles appear as brilliant specks of light. Following a single particle causes the particle to move at a constant speed. It passes across the medium in a succession of brief straight-line courses, shifting directions suddenly. Brownian movement or motion is the continuous quick zig-zag movement done by a colloidal particle in the dispersion medium.
Heterogeneous Property: According to an ultramicroscopic investigation, colloidal dispersion is a heterogeneous system consisting of a continuous dispersion medium and a discontinuous disperse phase.
Visibility: Because of their tiny size, colloidal particles cannot be seen with the naked eye or under a microscope. In visible spectra, the shortest wavelength is about 4000 A. As a result, humans can’t see anything smaller than 200m, colloidal particles are smaller than 200pm. To determine the size and shape of colloidal particles, new techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM) have recently been used.
Colligative Property: Colloidal particles are larger aggregates with colligative properties. The number of particles affects the colligative qualities. The colligative characteristics are lower because there are fewer particles in this solution than in a real solution. As a result, colligative qualities like osmotic pressure have values. Compared to the values indicated by actual solutions at the same concentration, the decrease in freezing point and the increase in boiling point are of modest order.
Surface Tension and Viscosity: Lyophilic sols have a greater viscosity and lower surface tension than the dispersion medium, whereas lyophobic sols have a viscosity and surface tension almost identical to the dispersion medium.
Color: A large number of sols are colored. Sol particles may scatter light rays. The wavelength of dispersed light by the sol particles determines the sol’s color, which is determined by the size of the sol particles. The color of the colloidal solution varies depending on how the observer receives the light. Consider a silver sol (colloidal solution of the same material) with several particle types. The sols are discovered to be of various colors.
Tyndall Effect: When a powerful light beam is passed through a sol and seen from the appropriate angle, it appears as a hazy beam or cone. Because sol particles absorb light energy and release it in all directions in space, this is the case. This scattering of light illuminates the beam’s path in the colloidal dispersion. The Tyndall effect is a phenomenon that occurs when sol particles scatter light. The Tyndall beam refers to the illuminating beam or cone created by the scattering of light by the sol particles. The Tyndall effect is well-known, as shown by the hazy lighting of a film projector in a smoke-filled theater or the light beams from a car’s headlights on a sandy road.
Conclusion
A colloid is a mixture in which one or more chemicals are scattered throughout a solid, liquid, or gaseous media as relatively large solid particles or liquid droplets. Due to the electrical charge of colloid particles, they remain scattered and do not settle despite gravity. They’re found all over nature, and they’re used in a variety of technological applications.
