The event of attracting and keeping the molecule of a substance on the surface of a solid is called adsorption. This results in an increased concentration on the surface than in the bulk. The expanse of adsorption of a gas on a solid material depends on the following factors: surface area of the solid, temperature of the gas, nature of the gas, the pressure of the gas, and nature of solid.
- Adsorbate – The substance that is absorbed. It is held by weak van der Waals forces in physisorption whereas in chemisorption it is held by a strong chemical bond.
- Adsorbent – The substance on which adsorption occurs.
- Adsorption isotherm – It is defined as the relationship between the pressure of the gas and extent of adsorption at a constant temperature.
Types Of Catalysis
A substance that enhances the rate of a chemical reaction without getting itself consumed by the reaction is called a catalyst. It does not undergo any change and can be recovered in a chemically unchanged form. The event occurring with a catalyst is known as catalysis.
- Homogeneous catalysis – When the catalyst and reactants are in the same phase it is called homogeneous catalysis.
- Heterogeneous catalysis – When the catalyst and reactants are in a different phase it is called heterogeneous catalysis.
Few Important Questions
- Explain the difference between absorption and adsorption with an example.
- Define lyophobic and lyophilic sols with one example each. Also, explain which sol is easily coagulated and why?
- Explain how emulsion is stabilized with emulsifiers. Name any two emulsifiers.
- What is aerosol? Write one example
- Define enzymes and explain enzyme catalysis mechanism.
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