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प्रश्न
What is the role of adsorption in heterogenous catalysis?
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उत्तर
The role of heterogeneous catalysts can be explained in terms of adsorption of reactants on the surface of the catalyst.
The adsorption helps the reaction in the following ways:
(i) Adsorption increases the concentration of reactants on the surface of the catalyst. Due to increased concentration of the reactants, the reactions proceed rapidly.
(ii) Adsorbed molecules get dissociated to form active species like free radicals which react faster than molecules.
(iii) The adsorbed molecules are not free to move about and, therefore, they collide with other molecules on the surface.
(iv) The heat of adsorption evolved acts as energy of activation for the reaction (chemisorption).
Example: Adsorption of molecules of the reactant at the active site.
Occurrence of chemical reaction on the surface of catalyst
Desorption of product molecules
Example:
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संबंधित प्रश्न
Give reasons for the following observations:
Physisorption decreases with increase in temperature.
What is the effect of temperature on chemisorption ?
Why is adsorption always exothermic?
Write any two characteristics of chemisorption.
Give reason why a finely divided substance is more effective as an adsorbent.
What are the factors which influence the adsorption of a gas on a solid?
Answer in one sentence:
Name type of adsorption in which vander Waals focres are present.
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Which of the following is an example of physisorption?
Which among the following is true for chemisorption?
The extent of adsorption increases with the ____________.
Physical adsorption of a gaseous species may change to chemical adsorption with ______.
Give an example where physisorption changes to chemisorption with rise in temperature. Explain the reason for change.
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Reason R : Gases with lower critical temperatures are readily adsorbed by activated charcoal.
In light of the above statements, choose the correct answer from the options given below.
