solution vs colloid
Mixture is a collection of different substances, which are physically combined, but do not join chemically. Mixtures show different physical or chemical properties than the individual substances. Solutions and colloids are two such mixtures with different properties. In these mixtures, solid, gaseous or liquid substances are mixed in different ratios.
What is a Solution?
A solution is a homogeneous mixture of two or more substances. It is called a homogenous mixture, because the composition is uniform throughout the solution. The components of a solution are mainly of two types, solutes and the solvent. Solvent dissolves the solutes and form a uniform solution. So, normally solvent amount is higher than the solute quantity. All the particles in a solution have the size of a molecule or an ion, so they cannot be observed by the naked eye. The solutions can have a color if the solvent or the solutes can absorb visible light. However, solutions are typically transparent. Solvents can be in a liquid, gaseous or solid state. Most common solvents are liquids. Among liquids, water is considered as a universal solvent, because it can dissolve many substances than any other solvent. Gas, solid or any other liquid solute can be dissolved in liquid solvents. In gas solvents, only gas solutes can be dissolved. There is a limit to the amount of solutes that can be added to a certain amount of solvent. The solution is said to be saturated if the maximum amount of the solute is added to the solvent. If there is a very low amount of solutes, the solution is diluted, and if there is a high amount of solutes in the solution, it is a concentrated solution. By measuring the concentration of a solution, we can get an idea about the amount of solutes in the solution.
What is a Colloid?
Colloidal solution is seen as a homogeneous mixture, but it also can be heterogeneous (e.g.: milk, fog). The particles in colloidal solutions are of intermediate size (larger than molecules) compared to particles in solutions and suspensions. But, like the particles in solutions, they are invisible to the naked eye and cannot be filtered using a filter paper. The particles in a colloid are termed as dispersed material, and the dispersing medium is analogous to the solvent in a solution. According to the dispersed material and the medium, there are different types of colloids. For instance, if a gas is dispersed in a liquid medium, the resulted colloid is ‘foam’ (e.g.: whipped cream). If two liquids are combined together, a colloid known as emulsion can be resulted (e.g.: milk). The particles distributed within the colloidal medium do not settle down if it is left still. Colloidal solutions are translucent or opaque. Sometimes particles in a colloid can be separated out by centrifugation or coagulation. For example, the proteins in milk are coagulated when supplied heat or added an acid.
Solution Vs Colloid
- The particles in a colloid are often bigger than the solute particles in a solution.
- Solutions are completely homogenous compared to colloids, which also can be a heterogeneous mixture.
- Colloidal mixtures appeared to be opaque or translucent, but solutions are transparent.