A solution is defined a homogenous mixture which mainly comprises of two components namely solute and solvent. For example, salt and sugar is a good illustration of a solution. A solution can be categorized into several components.
On the basis of physical states of solvent and solute can be categorized as solid, liquid and gaseous solutions.
In solid solutions, solute and solvent are in solid state. For example ceramics, and polymer blends. In liquid solutions, solid, gas or liquid is mixed in a liquid state. Gaseous solutions are usually homogenous mixtures of gases like air. Depending upon a number of solutions and solute, it can be classified into dilute and concentrated solutions.
Types of Solutions
Depending upon the dissolution of the solute in the solvent, solutions can be categorized into supersaturated, unsaturated and saturated solutions.
On the Basis of Water as Solvent
Based on the whether the solvent is water or not, solutions are of two types.
- Aqueous solutions: These solutions have water as the solvent. Examples of such solutions are sugar in water, carbon dioxide in water, etc.
- Non-Aqueous Solutions: These solutions have a solvent that is not water. It could be ether, benzene, petrol, carbon tetrachloride etc. Common examples include sulfur in carbon disulphide, naphthalene in benzene, etc.
On the Basis of the Amount of Solute Added
Based on the amount of solute present in the solution, we can classify them into the following types.
- Unsaturated Solution: An unsaturated is one that can dissolve more solute at a definite temperature. It means that we can still add more solute to the solvent.
- Saturated Solution: A solution is said to be saturated when we can’t add any more solute to the solvent. This means that the solution can’t dissolve any more solute at a definite temperature.
- Supersaturated Solution: A supersaturated solution is one where the solute is present in an excess amount. This solute is dissolved forcefully by raising the temperature or pressure of the solution. These generally crystal out in the bottom by the method called crystallisation.
On the Basis of Amount of Solvent Added
- Concentrated Solution: A concentrated solution has large amounts of solute in the given solvent. Examples include Brine solution, Orange juice, dark colour tea.
- Dilute Solution: A dilute solution has a small amount of solute in a large amount of solvent. Examples include Salt solution, light colour tea.
On the Basis of Concentration of Solute in Two Solutions
Let us consider a cell placed in a solution in a beaker. Based on the concentration of solute in two solvents( in the cell and in the beaker), we can have the following types of solutions:
- Isotonic Solution: These solutions have the same concentration of the solute in it. Therefore, water moves across the cell from the solution in the beaker in both directions.
- Hypertonic Solution: The solution kept in beaker has a higher concentration of solute in it so water comes out of the cell and into the solution in beaker causing the cell to plasmolyze/shrink.
- Hypotonic Solution: The solution kept in beaker has a lower concentration of solute in it so water moves into the cell causing cells to swell up and finally burst.