In this work, we mainly focus on the SA-AM and SA-DMA systems consisting of the same number (n) of sulfuric acid and base molecules. The intensive properties of a given cluster system should, with increasing cluster size, approach the properties of a bulk system. To gain insight into the intensive binding properties of clusters, we define the average binding quantity (∆G = ∆G bind n) as the binding free energy per acid-base pair. The ∆G is a measure of the average cluster stability. Also, it should converge to the free energy of an acid-base pair evaporation from its bulk system with a flat surface.