Surface chemistry is an important branch of chemistry. It deals with the study of the phenomenon occurring at the interface of two phases of the matter. Here surface represents the physical boundary of any condensed phase such as liquid or solid. It separates one phase from the other one. For example, interface existing between two immiscible liquids such as oil and water and between a metal and a gas. Class 12 Chemistry Chapter 5 is really interesting and essential for the students for further study also.
Some subtopics of Surface Chemistry are Adsorption, the distinction between Adsorption and Absorption, Mechanism of Adsorption, Types of Adsorption, Adsorption Isotherms, Adsorption from Solution Phase, Applications of Adsorption, Catalysis, Homogeneous and Heterogeneous Catalysis, Adsorption Theory of Heterogeneous Catalysis, Shape-Selective Catalysis by Zeolites, Enzyme Catalysis, Catalysts in Industry, Colloids, Classification of Colloids, Classification Based on the Physical State of Dispersed Phase and Dispersion Medium, Classification Based on the Nature of Interaction between Dispersed Phase and Dispersion Medium, Classification Based on the Type of Particles of the Dispersed Phase, Multimolecular, Macromolecular, and Associated Colloids, Preparation of Colloids, Purification of Colloidal Solutions, Properties of Colloidal Solutions, Emulsions and Colloids around Us.
This chapter deals with features related to surface chemistry like adsorption, catalysis, and colloids which are comprising emulsions and gels. After a study of this chapter, students will be able to describe the interfacial phenomenon and its significance. The chapter defines the adsorption and classifies into physical and chemical adsorption. Further, it explains the mechanism of adsorption with an explanation of the factors controlling adsorption from the gases and solutions on the solids. It also explains the adsorption on the basis of the Freundlich adsorption isotherms principle.
Some other concepts are the role of catalysts in industry, nature of the colloidal state, etc. Students will learn about the preparation, properties, and purification of the colloids. They will learn the classification of emulsions and descriptions of their preparation and properties with the phenomenon of gel formation too.
Adsorption is the phenomenon of attracting and retaining the molecules of any substance on the surface of the liquid or solid. Adsorption may be Physical adsorption (physisorption) or Chemical adsorption (Chemisorption) type. On the other hand, desorption is the reverse of adsorption which involves the removal of the substance adsorbed from the surface. And it is being done by Reducing the pressure and by heating. Students will learn the factors affecting the extent of adsorption like the nature of adsorbent and adsorbate, Temperature and Pressure of the gas, etc.
Catalyst substance is responsible to increase the rate of a reaction without participating in it. Catalysts are always useful in very small amounts and speed up the reaction by decreasing the potential energy activation barrier. These are of two types, which are Homogeneous catalysis and Heterogeneous catalysis. Student will learn their properties and features like activity and selectivity. Students will learn that enzymes are biological catalysts. These are more efficient than the chemical catalysts. This specific action of the enzyme is due to the presence of a specific and active site present on its surface. Thus this chapter will help the students to understand many chemical and natural phenomena.