JEE Main levelOne or more correct optionsDifficulty 2 of 3sc029
Which of the following statements about physisorption are correct?
AIts extent decreases when temperature is raised at constant pressure
BMultilayer adsorption can occur, especially at high pressure
CIts enthalpy of adsorption is low, about 20 to 40kJmol−1
DIt is highly specific, occurring only for particular gas-solid pairs
Answer: A, B, C
Physisorption is exothermic and weak (van der Waals), so it falls with temperature and has a low enthalpy. It is non-specific and can form multilayers at high pressure. Statement 4 describes chemisorption.