Many students find the transition from first-year general chemistry to second-year organic chemistry a daunting task. There are many reasons for this, not the least of which is their lack of a solid understanding and appreciation of the importance of some basic concepts and principles from general chemistry that play an extremely critical role in organic chemistry. One such concept is the -log of the acid dissociation constant, p"K"[subscript a]. This article reviews eleven key organic chemical outcomes that can be predicted from knowledge of p"K"[subscript a], highlighting its exceptional value as a physical quantity. (Contains 6 tables and 6 figures.)