Other Classifications of Mixtures: Particle Size and Physical State Basis | Nature of Matter - Class IX
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Other classifications of mixtures
Basis of the classification of mixtures
As we already discussed, mixtures can be classified into two types as homogeneous mixture and heterogeneous mixture on the basis of chemical composition.
Mixtures can also be classified into different types on the basis of the particle size and the physical states of their components as follows.
(A) On the basis of particle size or nature of dispersed particles
(i) Solution
(ii) Suspension
(iii)Colloidal solution
(B) On the basis of physical states of their components
(i) Solid-solid mixtures
(ii) Solid-liquid mixtures
(iii) Solid-gas mixtures
(iv) Liquid-liquid mixtures
(v) Liquid-gas mixtures
(vi) Gas-gas mixtures
(A) On the basis of particle size or nature of dispersed particles
(i) Solution
Solution is a homogeneous mixture of two or more substances.
Examples: aqueous solution of salt, alloys, air, etc.
(ii) Suspension
A suspension is a heterogeneous mixture in which the solute (component present in lesser quantity) particles do not dissolve in solvent (component present in larger quantity), i.e., remain suspended and they settle down on standing.
Examples: mud in water, sand in water, etc.
(iii) Colloidal solution
Colloidal solution is a mixture in which very small solute particles are dispersed throughout the solvent and do not settle down on standing.
Examples: milk, fog, starch solution, etc.
Properties of a solution, a suspension and a colloid
| Solution | Suspension | Colloid |
|---|---|---|
| A solution is a homogeneous mixture | Suspension is a heterogeneous mixture. | A colloid is a heterogeneous mixture. |
| The particles of a solution are smaller than 1nm $(10^{-9}m)$ in diameter. So, they cannot be seen by naked eyes. | The particles of a suspension can be seen by the naked eye. | The particles of a colloid are too small to be seen individually by naked eyes. |
| Because of very small particles, they do not scatter a beam of light passing through the solution. So, the path of light is invisible in a solution. | The particles of a suspension scatter a beam of light passing through it. So, the path of light is visible. | The particles of a colloid are big enough to scatter a beam of light passing through it. So, the path of light is also visible in it. |
| The solute particles cannot be separated from the mixture by filtration method. Also, the solute particles do not settle down when left undisturbed, i.e., a solution is stable. | The solute particles can be separated from the mixture by filtration method. They settle down when a suspension left undisturbed, i.e., a suspension is unstable. | They do not settle down when left undisturbed, i.e., a colloid is quite stable. |
Key Remarks
* The component of the solution that dissolves the other component in it ( usually the component present in larger amount) is called solvent while the component of the solution that is dissolved in the solvent (usually present in lesser quantity) is called solute.
* A solution can be in any form of solid, liquid and gas. For example, an alloy (solid solution), aqueous solution of salt (liquid solution) and air (gaseous solution).
* Alloys are the mixtures of two or more metals or a metal and a non-metal.
* Alloys cannot be separated into their components by physical methods, but still it is considered as a mixture because it shows the properties of its constituents and can have variable composition.
* A solution can be in any form of solid, liquid and gas. For example, an alloy (solid solution), aqueous solution of salt (liquid solution) and air (gaseous solution).
* Alloys are the mixtures of two or more metals or a metal and a non-metal.
* Alloys cannot be separated into their components by physical methods, but still it is considered as a mixture because it shows the properties of its constituents and can have variable composition.
(B) On the basis of physical states of their components
(i) Solid-solid mixtures
A mixture made by mixing two or more different solids without any chemical reaction is called solid-solid mixture.
Examples: sand and salt, sand and iron fillings, brass, etc.
(ii) Solid-liquid mixtures
A mixture made by mixing a solid with a liquid without any chemical reaction is called solid-liquid mixture.
Examples: salt in water, sand in water, iodine in carbon tetrachloride $(CCl_4)$, etc.
(iii) Solid-gas mixtures
A mixture made by mixing a solid with a gas without any chemical reaction is called solid-gas mixture.
Examples: dust in air, hydrogen gas adsorbed on Palladium (Pd), Chimneys smoke, etc.
(iv) Liquid-liquid mixtures
A mixture made by mixing a liquid with another liquid without any chemical reaction is called liquid-liquid mixture.
Examples: alcohol and water, benzene and toulene, oil and water, etc.
(v) Liquid-gas mixtures
A mixture made by mixing a liquid with a gas without any chemical reaction is called liquid-gas mixture.
Examples: soda water, liquor ammonia, fog, etc.
(vi) Gas-gas mixtures
A mixture made by mixing a gas with another gas without any chemical reaction is called gas-gas mixture.
Examples: air, natural gas, helium and oxygen mixture in a balloon, etc.
| Type of mixture | Homogeneous | Heterogeneous | |
|---|---|---|---|
| Solid-Solid | stainless steel, brass, bronze | Iron and sulphur | |
| Solid-Liquid | Nacl in water, iodine in $CCl_4$ | sand in water | |
| Solid-Gas | smoke | ||
| Liquid-Liquid | alcohol and water, benzene and toulene | oil and water | |
| Liquid-Gas | liquor ammonia, soda water | foam, mist | |
| Gas-Gas | Air |
Key Remarks
*In liquid - liquid mixtures, the liquids that mix completely with each other to form a single uniform layer are called miscible liquids. For example, alcohol and water.
*In liquid - liquid mixtures, the liquids that do not mix completely and form different layers are called immiscible liquids. For example, oil and water.
*In liquid - liquid mixtures, the liquids that do not mix completely and form different layers are called immiscible liquids. For example, oil and water.
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