Advertisements
Advertisements
प्रश्न
Why is adsorption always exothermic?
Advertisements
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.
APPEARS IN
संबंधित प्रश्न
Give reasons for the following observations:
Physisorption decreases with increase in temperature.
Differentiate between adsorbtion and absorption.
Give reason why a finely divided substance is more effective as an adsorbent.
Which of the following compounds is formed when tungsten adsorbs oxygen gas?
Which of the following is true about chemisorption?
Which among the following is a property of physisorption?
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 do physisorption and chemisorption behave differently with rise in temperature?
Which among the following is a false statement?
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:-
