Colloids & it's Classifications:

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Colloids are suspensions in which the suspended particles are larger than molecules but too small to drop out of the suspension due to gravity. Colloidal state is the intermediate state between true solution and suspension. There are several types of colloidal solutions:

1. Solid dispersed in liquid --- called Sol. (e.g. paint)
2. Solid dispersed in gas - called aerosol. (e.g. fog and smoke)
3. Liquid dispersed in liquid - called emulsion. (e.g. milk)
4. Liquid dispersed in solid - called gel. (e.g. Jellies, curd )
5. Gas dispersed in liquid - called foam. (e.g. froths of air)
6. Solid dispersed in solid - called solid sol (e.g. Ruby glass, Gems)

Natural applications of colloids can be seen in Blood, soils, fog, mist, rain, blue color of sky.

Tyndall effect:

The ability of a Colloid to scatter light. The beam of light can be seen through the colloid. The illuminated path is called Tyndall cone.

Technical applications of colloids are purification of drinking water, medicines, tanning, cleaning action of soaps and detergents, rubber industry, paints, inks, plastics etc.

Colloids are classified into these topics:

Colloids:

• Classification of colloids.
• Colloidal solutions.

Preparation of colloidal solutions.
Purification of colloidal solutions.
Properties of colloidal solutions.

• Stability of colloids.
• Hardy-Schulz law & gold number.
• Liquids in liquids (emulsions).

Types of emulsions preparation.
Preparation and properties.

• Gels.
• General applications of colloids.

Natural Applications.
Technical Applications.
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