Question

Which one of the following characteristics is not correct for physical adsorption?

• A. Adsorption is spontaneous
• B. Adsorption increases with increase in temperature
• C. Adsorption on solids is reversible
• D. Both enthalpy and entropy of adsorption are negative

Answer 1

The correct option is B Adsorption increases with increase in temperature

As temperature increases desorption increases.
$\text{Adsorption+Adsorbate}\rightleftharpoons \text{Adsorbed state}+\Delta E$

Adsorption is exothermic process (forward direction), desorption is endothermic process (backward direction).

According to Le-Chatelier's principle, increase in temperature favours endothermic process.