Write four applications of colloids.

Colloids play a very significant role in nature and in our daily life. Some of the important applications of colloids are discussed below:

1)Medicines:

Medicines in colloidal form are easily adsorbed by the body tissues and hence are more effective.

2)Sewage disposal:

Colloidal particles of the dirt, mud etc. carry electric charge, hence when sewage water is passed through the plates kept at a high potential, the colloidal particles are coagulated due to electrophoresis and the suspended matter gets removed.

3)Purification of water:

The precipitation of colloidal impurities present in water can be done by adding certain electrolytes like alum etc. the negatively charged colloidal particles of impurities get neutralized by the Al3+ ions and settle down and pure water can be decanted off.

3)Cleansing action of soap:

Soap solution is colloidal in nature. It removes the dirt particles either by adsorption or by emulsifying the greasy matter sticking to the cloth.

5) Smoke precipitation: 

Smoke is also a colloidal system which mainly consists of charged particles of carbon depressed in air.