JEE Main · 2023 · 24 Jan 2023 · Shift 2 · Surface Chemistry

Physisorption rests on weak van der Waals forces, and its features follow from that. It is non-specific rather than highly specific, so that statement fails, and its enthalpy of adsorption is small, about $20\text{–}40\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$, so that one fails too. Being exothermic, the extent of physical adsorption falls as temperature rises, which is correct, and it builds up as multiple layers rather than a single layer, so that statement fails. No activation energy is required for it to proceed, which is correct. Two of the listed characteristics hold true.