Which of the following is less than zero during adsorption?
A. $\Delta G$
B. $\Delta S$
C. $\Delta H$
D. All of these

Hint: Adsorption is generally described as a surface phenomenon where particles are attached to the top layer of the material. In the process of adsorption, the molecules, atoms, or ions of all states of matter are in a dissolved state which are attached to the surface.

Complete step by step answer:
Adsorption can also be defined as a process that takes place on the surface of molecular species that involves the accumulation of a substance at its higher concentrations.
A. $\Delta G$ is the Gibbs free energy which is negative during adsorption because it is a spontaneous process i.e. in which release of energy takes place so it shows a negative value.
B. $\Delta S$ is the change in entropy where entropy is defined as randomness or disorder of the system as the particles adsorb the randomness of the particles goes on decreasing and the process becomes non-spontaneous in nature and the non-spontaneous process is negative in nature,
C. $\Delta H$ describes the change in enthalpy or basically, this process also describes whether the system absorbs heat or produces heat. In the adsorption process heat is absorbed which describes the reaction as exothermic in nature so we can say that the value is also negative.
So, the correct answer is “Option D”.

Note: Adsorption process mainly consists of adsorbate and adsorbent where adsorbate is the substance that is deposited on the surface of another substance and adsorbent is on which the surface of adsorbate adsorb.