Question
Which of the following statements is incorrect regarding physissorptions?
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It occurs because of vander Waal’s forces.
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More easily liquefiable gases are adsorbed readily.
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Under high pressure, it results into multimolecular layer on the adsorbent surface.
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Enthalpy of adsorption ( ∆Hadsorption) is low and positive
Solution
D.
Enthalpy of adsorption ( ∆Hadsorption) is low and positive
Enthalpy of adsorption in physisorption is negative
∆G = ∆H - T∆S
As the entropy decreases (∆S = –ve) the ∆H must be negative having a high magnitude. Therefore, the spontaneous adsorption will have negative enthalpy change.
