SURFACE CHEMISTRY

Adsorption Adsorbate, adsorbent, examples, distinction between adsorption and absorption. H, S and G for adsorption of gas on a solid. Physisorption and chemisorption-characteristics and differences. Factors affecting adsorption of a gas on a solid. Applications.
Catalysis Homogeneous and heterogeneous catalysis, examples, activity and selectivity of a catalyst, examples, shape selective catalysis, examples. Enzyme catalysis: examples, mechanism
Colloids Colloidal state-distinction of true solution, colloids, and suspension based on particle size.
Classification of colloids Types of colloidal systems- examples, lyophilic and lyophobic— differences and examples, macromolecular, multimolecular and associated colloids, examples, formation of micelle, cleansing action of soaps. Preparation of colloids-chemical methods sulphur and ferric hydroxide sols, Bredig’s arc method for metal sols, peptization. Purification– dialysis, electro-dialysis, ultrafiltration Properties of colloids: Tyndall effect, Brownian movement, charge on colloidal particles, examples, electrophoresis, coagulation – methods of coagulation of lyophobic sols, HardySchulze rule-examples, coagulating value. Protective colloid – example. Applications: In industries, medicines, purification of drinking water.
Emulsions Types, examples.
Colloids Around Us Applications of Colloids