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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
Write the differences between physisorption and chemisorption with respect to the following:
(i) Specificity
(ii) Temperature dependence
(iii) Reversibility and
(iv) Enthalpy change
Differentiate between adsorbtion and absorption.
Why is adsorption always exothermic?
Why are powdered substances more effective adsorbents than their crystalline forms?
Distinguish between the meaning of the terms adsorption and absorption. Give one example of.
Give reason why a finely divided substance is more effective as an adsorbent.
Write one similarity between Physisorption and Chemisorption
How does chemisorption vary with temperature?
Which of the following is an example of physisorption?
Which among the following is a property of physisorption?
Which among the following is true for chemisorption?
The extent of adsorption increases with the ____________.
The physical adsorption is due to ____________.
Which of the following is not a favourable condition for physical adsorption?
Why is chemisorption referred to as activated adsorption?
Why do physisorption and chemisorption behave differently with rise in temperature?
What is the role of diffusion in heterogenous catalysis?
Assertion: Detergents with low CMC are more economical to use.
Reason: Cleansing action of detergents involves the formation of micelles. These are formed when the concentration of detergents becomes equal to CMC.
Rate of physisorption increase with:-
Assertion A : Activated charcoal adsorbs SO2 more efficiently than CH4.
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.
