The correct option(s) related to adsorption processes is(are)

(A) First statement is correct as chemisorption results in a unimolecular layer and physisorption result in a multimolecular layer.

(B) Second statement is incorrect as enthalpy change during physisorption is of the range of $\left(20 - 40\right){kJmol}^{- 1}$.Gases with higher critical temperatures are readily adsorbed

(C) Chemisorption is an exothermic process with $\left(80 - 240\right){kJmol}^{- 1}$ as the enthalpy of adsorption.

(D) Lowering the temperature results in increase in the extent of physisorption.It decreases with increase of temperature.

Hence (A) and (D) are correct.