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Questions
What are the factors which influence the adsorption of a gas on a solid?
Describe the factors which affect the adsorption of gases on solids.
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Solution
There are various factors that affect the rate of adsorption of a gas on a solid surface.
- Nature of the gas: Easily liquefiable gases such as NH3, HCl, etc., are adsorbed to a great extent in comparison to gases such as H2, O2, etc. This is because Van der Waal’s forces are stronger in easily liquefiable gases.
- Surface area of the solid: The greater the surface area of the adsorbent, the greater is the adsorption of a gas on the solid surface.
- Effect of pressure: Adsorption is a reversible process and is accompanied by a decrease in pressure. Therefore, adsorption increases with an increase in pressure.
- Effect of temperature: Adsorption is an exothermic process. Thus, in accordance with Le-Chatelier’s principle, the magnitude of adsorption decreases with an increase in temperature.
RELATED QUESTIONS
Write the differences between physisorption and chemisorption with respect to the following:
(i) Specificity
(ii) Temperature dependence
(iii) Reversibility and
(iv) Enthalpy change
Give reasons for the following observations:
Physisorption decreases with increase in temperature.
Write any two characteristics of chemisorption.
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 reasons for the following observations :
Powdered substances are more effective adsorbents.
How does chemisorption vary with temperature?
Answer in one sentence:
Name type of adsorption in which the compound is formed.
Adsorption increases when ____________.
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.
What is the role of diffusion in heterogenous catalysis?
What is the role of adsorption in heterogenous catalysis?
A plot of 10 g (x/m) versus 10 g p for the adsorption of a gas on the surface of a solid gives a straight line with slope equal to:-
Adsorption play no role in:-
Write three differences between physisorption and chemisorption.
