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

(N/A) $(i)$ Lyophilic sols: Colloidal sols formed by mixing substances like gum,gelatin,or starch with a suitable dispersion medium are called lyophilic sols. These are reversible in nature,meaning they can be reconstituted by simply mixing the components again after separation.
$(ii)$ Lyophobic sols: Colloidal sols formed by substances like metals or their sulphides,which do not readily form sols with the dispersion medium,are called lyophobic sols. These require special methods for preparation and are irreversible in nature.
Hydrophobic (lyophobic) sols are easily coagulated because their stability depends solely on the presence of an electric charge on the colloidal particles. When this charge is neutralized by the addition of electrolytes,the particles aggregate and precipitate.