As the process of adsorption proceeds dynamically on a solid surface, what happens to the magnitude — Surface Chemistry Chemistry Question

💡 Solution & Explanation

Initially, adsorption is highly exothermic ($\Delta H$ is highly negative) because molecules adhere to the most highly energetic active sites. As more surface sites are occupied, the residual forces decrease, so $\Delta H$ becomes less and less negative. Simultaneously, $\Delta G$ approaches zero. At dynamic equilibrium, $\Delta G = 0$ and $\Delta H = T\Delta S$.