NEET Chemistry Surface Chemistry Questions Solved

BOARD

What are lyophilic and lyophobic colloids? Which of these sols can be easily 

coagulated on the addition of small amounts of electrolytes?

Lyophobic sols: Substances like metals, their sulphides, etc., when simply 

mixed with the dispersion medium do not form the colloidal sol. Their colloidal

sols can only be prepared by specific methods. They are not much hydrated

and are irreversible in nature. They are also called extrinsic colloids.

Example: AS2S3 sol.

Lyophilic sols: Liquid loving colloids in which there is affinity between

disperse phase and dispersion medium.

Example: Starch sol, Gum sol, Gelatin sol

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