Out of Lyophilic and Lyophobic sols, which can be easily coagulated on the addition of a small amount of electrolyte ?

Explanation

Depending upon the nature of interaction between the dispersed phase and the dispersion medium, colloids are divided into two categories :
(i) Lyophilic sols : The colloids in which the particles of the dispersed phase have a strong affinity for the dispersion medium are called lyophilic sols. These collidal solutions, even if precipitated, change back to the colloidal form simly by adding dispersion medium, So lyophilic sols are reversible in nahtre e.g., glue, starch, rubber, etc.
(ii) Lyophobic sols : The colloids in which particles of the dispersed phase have no or very little affinity for dispersion medium are called lyophobic sols. These are irreversible in nature i.e., once precipitated, they have little tendency to get back into the colloidal form on simply adding dispersion medium e.g., `As_2S_3 sol`.
Lyophobic sols need stabilising agents for teir preservation.