The homogeneous mixture of two or more components is called a Solution.
HOMOGENEOUS AND HETEROGENEOUS MIXTURE
(i) Homogeneous mixture: A mixture of two or more components having no distinguish phase is called homogeneous mixture.
The homogeneous mixture is generally referred to as a solution.
Example: When two spoons of salt are mixed in a glass of water, the mixture so obtained has no distinguish phase and this is called a solution.
Air is a mixture of different gases with no distinguish phase, thus, the air is often referred to as the solution.
In a homogeneous mixture, i.e. solution, the composition, and properties of the solution are uniform throughout.
(ii) Heterogeneous mixture: A mixture of two or more components with distinguish phase is called heterogeneous mixture.
Example: A mixture of mustard oil and water, in this mixture phases of water and mustard oil can be seen and distinguished clearly, and hence called heterogeneous mixture.
Fig: Heterogeneous mixture: oil and water
SOLUTE AND SOLVENT
Note: Physical state of solvent and solution is same.
Solutions which contain only two components are called binary solution. For example, a solution of salt in water is a type of binary solution, as it contains only two components.
Binary Solution = Solute + Solvent
Similarly, it is called ternary and quaternary if it is composed of three and four components, respectively.
Thus; a solution may be regarded as a single phase containing more than one component.
A solution in which relatively a small amount of solute is dissolved in large amount of solvent is called a dilute solution.
A solution in which relatively a large amount of the solute is present is called a concentrated solution.
Fig: Dilute and Concentrated Solution
PROPERTIES OF A SOLUTION
TYPES OF SOLUTION
In a solution, components may be solid, liquid or gas.
On this basis Solutions can be divided into the following three types:
1. Gaseous Solution: Solutions in which solvent is present is a gaseous state is called Gaseous solution.
Gaseous solutions can be divided into following three types on the basis of phases of solute and solvent;
(i) Gas - Gas Solution: Solutions in which solute and solvent both are gases; are called Gas-gas Solutions.
Example: solution (mixture) of nitrogen and oxygen, solution (mixture) of carbon dioxide and nitrogen, solution (mixture) of carbon dioxide and oxygen, etc.
(ii) Liquid Gas Solution: Solutions, in which solute is in liquid state and solvent is in a gaseous state, are called Liquid-Gas Solution.
Example: solution (mixture) of chloroform in nitrogen gas.
(iii) Solid Gas Solution: Solutions, in which solute is in solid state and solvent is in gasesous state, are called Solid-Gas Solutions.
Example: Solution (mixture) of camphor in nitrogen gas.
2. Liquid Solution: Solutions, in which solvent is present in liquid state, are called Liquid solutions.
Liquid solutions can be classified into following three types:
(i) Gas - Liquid Solution: Solutions having solute in gaseous state and solvent in liquid state, are called Gas - Liquid Solutions.
Example: Solution (mixture) of oxygen in water, mixture of carbon dioxide in water. Coca cola, a beverage, is an example of gas - liquid solution, as it has carbon dioxide dissolved in water.
(ii) Liquid - Liquid Solution: Solutions, in which solute and solvent both are present in liquid state, are called liquid liquid solutions.
Example: Vinegar solution, vinegar is the mixture of ethanoic acid and water. Solution of ethanol in water, etc.
(iii) Solid - Liquid Solution: Solutions, in which solutes present in solid state and solvent is in liquid state, are called solid liquid solutions.
Example: Solution of salt in water, solution of glucose in water, etc.
Fig: Glucose in water
3. Solid Solution: Solutions having solvent in the solid state, are called solid solutions.
The solid solution can be divided into the following three categories:(i) Gas - Solid Solution: Solutions having solvent in solid state and solute in the gasesous state are called gas-solid solutions.
Example: solution of hydrogen in palladium.
(ii) Liquid - Solid Solution: Solutions having solvent in solid state and solute in the liquid state are called liquid-solid solutions.
Example: amalgam of mercury with sodium.
(iii) Solid - solid solution: Solutions having solvent and solute both in the solid state are called solid – solid solutions.
Example: Solution of gold and copper.