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प्रश्न
Give an example where physisorption changes to chemisorption with rise in temperature. Explain the reason for change.
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उत्तर
The process of physisorption for example that of H2 on finely divided nickel, involves weak van der Waals’ forces. With increase in temperature, hydrogen molecules dissociate into hydrogen atoms which are held on the surface by chemisorption.
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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
Give reasons for the following observations:
Physisorption decreases with increase in temperature.
What is the effect of temperature on chemisorption ?
Write any two characteristics of chemisorption.
What is the difference between physisorption and chemisorption?
Write one similarity between Physisorption and Chemisorption
Answer in one sentence:
Name type of adsorption in which vander Waals focres are present.
Which of the following is true about chemisorption?
Powdered substances are more effective adsorbents than their crystalline forms because ____________.
The physical adsorption is due to ____________.
In which of the following reactions heterogenous catalysis is involved?
(a) \[\ce{2SO2 (g) + O2 (g) ->[NO(g)] 2SO3 (g)}\]
(b) \[\ce{2SO2 (g) ->[Pt(s)] 2SO3 (g)}\]
(c) \[\ce{N2 (g) + 3H2 (g) ->[Fe(s)] 2NH3 (g)}\]
(d) \[\ce{CH3COOCH3 (l) + H2O (l) ->[HCI(l)] CH3COOH (aq) + CH3OH (aq)}\]
Why is it important to have clean surface in surface studies?
Why do physisorption and chemisorption behave differently with rise in temperature?
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.
Which among the following is a false statement?
In physical adsorption, gas molecules are bound on the solid surface by
Rate of physisorption increase with:-
Write three differences between physisorption and chemisorption.
