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प्रश्न
Why is adsorption always exothermic?
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उत्तर
ΔH is always negative because during adsorption, the surface energy decreases in the form of heat. Furthermore, ΔS is negative because when a gas is adsorbed on a solid surface, its movement is restricted; this leads to a decrease in the entropy of the gas. Now, for a process to be spontaneous, ΔG should be negative.
∴ ΔG = ΔH − TΔS
Because ΔS is negative, TΔS becomes positive. Therefore, ΔH has to be highly negative for the spontaneous process to make ΔG negative. Hence, adsorption is always exothermic.
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संबंधित प्रश्न
Give reasons for the following observations:
Physisorption decreases with increase in temperature.
Differentiate between adsorbtion and absorption.
What is the effect of temperature on chemisorption ?
What is the difference between physisorption and chemisorption?
Write one similarity between Physisorption and Chemisorption
Physisorption is reversible while chemisorption is irreversible. Why ?
The extent of adsorption increases with the ____________.
Extent of physisorption of a gas increases with ______.
Which of the following is not a favourable condition for physical adsorption?
What is the role of adsorption in heterogenous catalysis?
