What are the properties of a colloid?

What are the properties of a colloid? 

Answer: Properties of a colloid are: 

1. Heterogeneous nature: Colloid or Sol is heterogeneous in nature i.e. it can be seen only with a powerful microscope. 

2. Particle Size: Colloid particle size lies between 1nm (10-9 m) to 100 nm (10-7 m) 

3. Separation of colloidal particles by filtration: Colloidal particles cannot be separated from the mixture by the process of filtration. But, a special

technique of separation known as centrifugation. 

4. Brownian Motion: When seen under microscope, the colloidal particles in a colloid are seen to be moving in a random fashion, called Brownian motion. 

5. Stability: They do not settle down when left undisturbed, that is, a colloid is quite stable. 

6. Tyndall effect: Colloid exhibit Tyndall  effect. When a light is passed through sol kept in dark room, the path of light beam is visible. It is due to scattering of light by colloidal particles and this effect is called

Tyndall effect. 

7. Electrophoresis: Man colloidal particles may have electrical charge (+ve or -ve) on them. When an electric current passes through a sol, colloid particles move towards opposite charged electrodes. This process is called electrophoresis.