Chemisorption has the following traits:

(A)    High enthalpy of adsorption

(B)    Reversible

(C)    Favoured by high temperature

(D)   Requires low activation enthalpy

Choose the correct answer from the options given below:

A, C only

The correct answer is (2) A, C only.

Chemisorption is a type of adsorption in which chemical bonds are formed between the adsorbate (the substance being adsorbed) and the adsorbent (the surface on which adsorption occurs). Let's go through each trait:

(A) High enthalpy of adsorption: This is true for chemisorption. In chemisorption, strong chemical bonds are formed between the adsorbate and adsorbent, resulting in a high enthalpy of adsorption.

(B) Reversible: Chemisorption is typically not reversible under the same conditions. It often involves the formation of strong chemical bonds, which are not easily broken by simple physical processes like desorption.

(C) Favoured by high temperature: This is generally true for chemisorption. Higher temperatures provide more energy for the activation of chemical reactions, making chemisorption more favorable at higher temperatures.

(D) Requires low activation enthalpy: This is not true for chemisorption. Chemisorption typically involves the formation of strong chemical bonds, which require a significant activation energy (enthalpy) to overcome the energy barrier and occur.

Based on the above analysis, the correct answer is: (2) A, C only