Homoassociation (original) (raw)

In acid–base chemistry, homoassociation (an IUPAC term) is an association between a base and its conjugate acid through a hydrogen bond. The alternate term homoconjugation also has wide usage, but is ambiguous because it has another meaning in organic chemistry (see Conjugated system#Mechanism). 2 HF H2F+ + F− (autoionization of HF)HF + F− HF2− (homoassociation) Overall: 3 HF HF2− + H2F+ The bifluoride anion (HF2−) encourages the ionization of HF by stabilizing the F−. Thus, the usual ionization constant for hydrofluoric acid (10−3.15) understates the acidity of concentrated solutions of HF.