Chemistry

Classification of colloids
Colloids are classified according to the physical state of dispersed phase (solute) and the dispersion medium (solvent). Most of the colloids can be classified into the following seven groups.
Sol: Sol is a colloid in which tiny solid particles are dispersed in a liquid medium.
Example. Ink, Soap solution, starch solution and most paints.
Solid sol : Solid sol is a colloid in which solid particles are dispersed in a solid medium.
Example. Coloured gemstones (like ruby glass).
Aerosol : An aerosol is a colloid in which a solid or liquid is dispersed in a gas (including air).
Example. The examples of aerosols in which a solid is dispersed in a gas are : Smoke (which is soot in air) and Automobile exhausts. The examples of aerosols in which a liquid is dispersed in a gas are : Hairspray, Fog, Mist and clouds.
Emulsion : An emulsion is a colloid in which minute droplets of one liquid are dispersed in another liquid which is not miscible with it.
Example. Milk, butter and Face cream.
Foam : The foam is a colloid in which a gas is dispersed in a liquid medium.
Example. Fire-extinguisher foam ; Soap bubbles, shaving cream and Beer foam.
Solid foam : The solid foam is a colloid in which a gas is dispersed in a solid medium.
Example. Insulating foam, foam rubber and Sponge.
Gel : The gel is a semi-solid colloid in which there is a continuous network of solid particles dispersed in a liquid.
Example. Jellies and Gelating.