Class 12 Chemistry - Chapter Surface Chemistry NCERT Solutions | Discuss the effect of pressure and tempe
Discuss the effect of pressure and temperature on the adsorption of gases on solids.
Effect of pressure & temperature-
According to Le Chatelier’s principle, the magnitude of adsorption should increase with fall in temperature & since adsorption of a gas leads to decrease of pressure, the magnitude of adsorption increases with increase in pressure. If a equilibrium is subjected to a stress, the equilibrium shifts in such a way as to reduce the stress. Graphically, the variation of adsorption with pressure at given constant temperature is given by adsorption isotherm.
The relationship between magnitude of adsorption & pressure can be expressed mathematically by Freundlich Adsorption isotherm i.e a = Kpn where a is the amount of gas adsorbed per unit mass of adsorbent at pressure p & K & n are constant depending upon the nature of gas & adsorbent.The value of n is less than 1 & therefore a does not increase as rapidly as p.
The effect of temperature on the extent of adsorption at a given pressure of adsorbate is given by adsorption isobar.
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