Question

Adsorption is accompanied by the evolution of heat, so, according Le-Chatelier principle, the amount of substance adsorbed should:

• A. increase with decrease in $T$
• B. increase with increase in $T$
• C. decrease with decrease in $T$
• D. decrease with increase in $T$

Answer 1

Answer: (A)

increase with decrease in $T$

Adsorption is accompanied by the evolution of heat. So, according to the Le-Chatelier principle, the amount of substance adsorbed should increase with decrease in temperature.

Adsorption is accompanied by the evolution of heat, so, it is exothermic process.

Reactants $\rightleftharpoons$ products $+$ heat.

As the temperature is lowered, heat is removed from the system. So, the equilibrium will shift in the forward direction so that more and more heat is produced. This will nullify the effect of the removal of heat. This is in accordance with the Le-Chatelier principle.