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Explain the factors affecting adsorption. |
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Answer» SOLUTION : Factors affecting ADSORPTION : The adsorption is well understood by considering the various factors affecting it. Qualitatively, the extent of surface adsorption depends on (i) Nature of adsorbent (II) Nature of adsorbate (iii) Pressure (iv) Concentration at a given temperature. (i) Surface area of adsorbent : As the adsorption is a surface phenomenon it depends on the surface area of adsorbent. i.e., higher the surface area, higher is the amount adsorbed. (ii) Nature of adsorbate : The nature of adsorbate can influence the adsorption. Gases LIKE `SO_2, NH_3, HCl "and" CO_2`are easily liquefiable as have greater vanderwaal's force of attraction. On the other hand, permanent gases like `H_2, N_2 "and" O_2`cannot be liquefied easily. These permanent gases are having low critical temperature and adsorbed slowly, while gases with high critical temperature are adsorbed readily. (iii) Effect of temperature : chemical adsorption is fast with increase pressure, it cannot alter the amount. In Physisorption, when pressure increases the amount of adsorption increases. (iv) Effect of pressure : When pressure increases, adsorption becomes steadily increase in case of chemisorption and increases in case of physisorption. |
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