Question

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

Answer 1

Lyophilic sols

• The term 'lyophilic' refers to liquid loving.
• ''Colloidal sols directly formed by mixing substances like rubber, gum, gelatine, starch, etc., with a suitable liquid (the dispersion medium) are called lyophilic sols.''
• These sols are also called reversible sols.
• Examples of lyophilic sols are rubber and gelatin.

Lyophobic sols

• The term 'lyophobic' refers to liquid hating.
• “Substances like metals, their sulfides, etc., when simply mixed with the dispersion medium do not form the colloidal sol. Such sols are called lyophobic sols”.
• These sols are also called irreversible sols.
• An example of lyophobic sols is arsenious sulfide sol.

Reason for the coagulation of hydrophobic sols

• The charge on the particle stabilizes hydrophobic sols.
• When the charge is removed by using an electrolyte, the particles tend to cluster together and form an aggregate or precipitate.