Colloids can be classified in many ways, and one important method is based on the dispersion medium (the continuous phase in which colloidal particles are dispersed). Here’s a clear breakdown:
Classification of Colloids Based on Dispersion Medium
- Aerosols
- Dispersion Medium: Gas
- Dispersed Phase: Solid or liquid
- Examples:
- Solid in gas → Smoke, dust in air
- Liquid in gas → Fog, mist, clouds, spray
- Foams
- Dispersion Medium: Liquid
- Dispersed Phase: Gas
- Examples: Soap lather, whipped cream, froth on beer
- Emulsions
- Dispersion Medium: Liquid
- Dispersed Phase: Liquid
- Examples: Milk (fat in water), butter, mayonnaise
- Sol
- Dispersion Medium: Liquid
- Dispersed Phase: Solid
- Examples: Paints, ink, starch solution, blood
- Gel
- Dispersion Medium: Solid
- Dispersed Phase: Liquid
- Examples: Jelly, cheese, butter, shoe polish
- Solid Sols
- Dispersion Medium: Solid
- Dispersed Phase: Solid
- Examples: Colored glass, some alloys, ruby glass
- Solid Foams
- Dispersion Medium: Solid
- Dispersed Phase: Gas
- Examples: Foam rubber, pumice stone, sponge
In short: Colloids are classified as aerosols, foams, emulsions, sols, gels, solid sols, and solid foams depending on whether the dispersion medium is gas, liquid, or solid.