Adsorption

Physical adsorption takes place with decrease in enthalpy thus exothermic change. It is physical adsorption and does not require activation. Thus, (a) is incorrect. Being physical adsorption H < 0 thus, (b) is correct. Exothermic reaction is favoured at low temperature thus (c) is incorrect. Physical adsorption is always reversible, thus (d) is incorrect.

Adsorption obeys Freundlich isotherm, which can be written as: where, = amount adsorbed per unit mass of adsorbent (mg/g), = equilibrium concentration of adsorbate in solution (mg/L or mg/g), , = constants depending on temperature and adsorbate-adsorbent system. Given data: From Freundlich isotherm, for the two points: Dividing the two equations to eliminate : Taking logarithm base 10 on both sides: Calculate the logs: Using and , so: Similarly, So, Now, find using one of the points, say , : We are asked to find adsorbed amount when mg/g: Final answer Answer:

Adsorption obeys Freundlich isotherm, which can be written as: where, = amount adsorbed per unit mass of adsorbent (mg/g), = equilibrium concentration of adsorbate in solution (mg/L or mg/g), , = constants depending on temperature and adsorbate-adsorbent system. Given data: From Freundlich isotherm, for the two points: Dividing the two equations to eliminate : Taking logarithm base 10 on both sides: Calculate the logs: Using and , so: Similarly, So, Now, find using one of the points, say , : We are asked to find adsorbed amount when mg/g: % Final answer Answer: