What are lyophilic and lyophobic sols ? give one example of each type.Why are hydrophobic sols easily coagulated ?

Lyophilic - lyophilic (liquid loving) this sols formed by direct mixing of substances like gum starch etc.with suitable liquid,called as lyophilic sols . This are called as reversible sol because if dispersion medium is separated from the dispersed phase it can be reconstructed just by mixing them.This sols are quite stable.Ex-Protein ,Starch.

Lyophobic -lyophobic (liquid hating) this sols don't formed by direct mixing of dispersed phase and dispersion media they require special methods for preparation.Ex-Sols of metal sulphides .

This Lyophobic(Hydrophobic-water hating) sols gets easily coagulated.Because they are less stable.their stability is only due to Charge If electrolyte is added to it opposite charge will attract and form coagulation easily.