5336 Pettit and Irving 1019. Ligands containing Elements of Group V. Purt I. By L. D. PETTITand H. M. N. H. IRVING. The acid dissociation constants of N-2-carboxyethyldiphenylamineand of its phosphorus and arsenic analogues [(C,H,),X(CH,*CH,-C0,H) ; X = N P or As] have been measured in 20% (v/v) aqueous dioxan at