Q13 of 46 Page 1

(a) Write the dispersed phase and dispersion medium of milk.

(b) Why is adsorption exothermic in nature?


(c) Write Freundlich adsorption isotherm for gases at high pressure.


(a) Both the dispersed phase and dispersion medium of milk is liquid. Milk is a type of emulsion.


(b) Adsorption is exothermic in nature because when a gas is adsorbed its movement becomes restricted and there is a decrease in entropy i.e. Δs = negative. For any process to be spontaneous, ΔG should be negative and ΔG = ΔH – TΔs.


During adsorption, -TΔs = positive (as Δs = negative) thus, ΔH will be sufficiently negative (ΔH> TΔs and ΔH = negative) so that ΔG will be negative and the process of adsorption becomes spontaneous. Therefore, Adsorption is an exothermic process.


(c) Freundlich adsorption isotherm seemed to approach saturation for gases at high pressure i.e. once the solid surface is saturated with adsorbate molecules, even if we increase the pressure no more adsorption will take place.


At high pressure, x/m = kp0


x/m = k i.e. a constant



Adsorption Isotherm


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