ANS:B - temperature decreases.

The rate of adsorption generally increases as the: temperature decreases. This relationship is described by the principle of adsorption equilibrium, which states that at a given temperature, there is a balance between the rate of adsorption (molecules adhering to the surface of the adsorbent) and the rate of desorption (molecules leaving the surface of the adsorbent). A lower temperature typically favors adsorption because it reduces the kinetic energy of the adsorbate molecules, making it easier for them to adhere to the surface of the adsorbent. Conversely, at higher temperatures, the kinetic energy of the adsorbate molecules increases, leading to more frequent collisions with the surface of the adsorbent and a higher rate of desorption. As a result, the overall rate of adsorption decreases as the temperature increases. The other options, such as temperature increases or pressure decreases, generally do not lead to an increase in the rate of adsorption. While increasing the size of the adsorbent might provide more surface area for adsorption to occur, it does not necessarily increase the rate of adsorption.