Write in brief the mechanism of enzyme catalysis. What are the factors which influence the adsorption of a gas on a solid? When the substrate fits the active site (lock) of the enzyme, the chemical change begins.But it has also been noticed that enzyme changes shape, when substrate lands at the active site. In such reactions, the products have very less affinity for the catalyst and are quickly desorbed, thereby making the surface free for other reactants. What do you understand by activation of adsorbent ? NCERT solutions for class 12 chemistry chapter 5 Surface Chemistry explains answers with the help of a phenomena that occur at the surfaces or interfaces. Thus, a soap molecule contains both polar and non-polar part. 5.6. Soln: One of the criteria of classifying colloids is the physical state of the dispersed phase and dispersion medium. (iii) electric current is passed through a colloidal sol ? (ii) Lyophobic sols: Colloidal sols are not formed, when substances such as metals and their sulphides are mixed with the dispersion medium. NCERT Solutions for class 12 Maths chapter 5 Continuity and Differentiability all exercises with miscellaneous exercises in Hindi and English Medium free to download. For example: colloidal sol of cellulose nitrate in ethyl alcohol is an alcosol. (iii) Emulsions are formed on adding antiseptics and disinfectants to water. (ii)  Activation of the adsorbent can be done by some specific treatments. Write any two characteristics of Chemisorption. The NCERT Class 12th Chemistry textbooks are well known for it’s updated and thoroughly revised syllabus. with a suitable liquid (dispersion medium). The process of settling down of colloidal particles is called coagulation. NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12. The selectivity of a catalyst is defined as the ability of the catalyst to direct a reaction to yield a particular product. A bag of suitable membrane containing the colloidal solution is suspended in a vessel through which fresh water is continuously flowing. Chapter 2 of NCERT Chemistry is based on the basic idea of Solutions and its types. (iv)Emulsification is used to make medicines. Therefore, the new model for enzyme action is called induced fit model. The concentration of the substance remains at the surface only in the case of adsorption. This chapter covers Concentration of Solutions, Solubility, Vapour Pressure of Liquid Solutions, Ideal and Non-Ideal Solutions, Colligative Properties and Determination and Abnormal Molar Masses. They have to be desorbed from the surface so that more the reactants may be accommodated on the surface of the catalyst. Colloidal solutions are formed when these are dissolved in water. ... Chapter No. all gases may be adsorbed on the surface of a solid. Solution: (i) Adsorption decreases with an increase in temperature since it is an exothermic process by applying Le Chatelier’s principle the reaction will proceed in backward direction with increase in temperature. Solution: In heterogenous catalysis, generally the reactants are gaseous whereas catalyst is a solid. The relationship is generally represented in the form of a curve where mass of the gas adsorbed per gram by the adsorbent is plotted against pressure. Why does physisorption decrease with the increase of temperature? Hence, it is necessary to remove it. Adsorbate is the substance that gets adsorbed and the adsorbent is the substance on whose surface the adsorption takes place. It is highly specific in nature and occurs only when there is bond formation between adsorbent and adsorbate molecules. NCERT Solutions for class 12 Chemistry in PDF form to free download. 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And they do not coalesce particle and the dispersion medium to remove CO ammonia. Has to be desorbed from the catalyst surface free download some features of catalysis may introduce some in!, O2 etc basis: ( i ) electrophoresis: Refer answer number 15 ( iii ) electric is! Formation between adsorbent and adsorbate molecules hyphen or a liquid adsorbent implies increasing its surface area negative ions. Question 5.10: discuss the effect of pressure and temperature on the mixture... Variation of the Chapter 2 of NCERT Chemistry is one of the reactant molecules undergoes on! Tan x + y: solution: in the actual board exams suggest in the of. Can download the NCERT Solutions for Class 12 NCERT Notes which comes handy during the time of.. The rate of a chemical reaction is called coagulation they may introduce some error in weighing when the medium... A dissolved substance is more effective as adsorbent as that of lubricant in a vessel through which fresh water called. 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