Question

From the following statements, which is/are correct?

• A. Physical adsorption is multilayer and non specific
• B. Chemical adsorption is generally monolayer and reversible in nature
• C. Physical adsorption is due to free valence electrons of atoms
• D. Chemical adsorption is stronger than physical adsorption and occurs at high temperature

Answer 1

Answer: (A), (D)

Chemical adsorption is stronger than physical adsorption and occurs at high temperature

Physical adsorption involves weak Van der Walls forces between the adsorbent and the adsorbate.
Chemical adsorption is due to chemical bonds - like ionic and covalent bonds. These are stronger when compared with bonds involved in physical adsorption. Chemical adsorption occurs at high temperatures due to a high activation energy.