Two earlier papers (J., 1941, 550; 1944, 411), which appeared under specific titles, are regarded as Parts XI and XI1 of this series.

No abstract

The dissociation constants of nine disubstituted benzoic acids, two trisubstituted benzoic acids, and three nitrophenols in water a t 25' have been determined by the conductivity method ; included are two series comprising dinitro-and chloronitro-benzoic acids. The results shed light on the operation of steric effects in the benzoic acid system. DISSOCIATION constants for dimethylbenzoic acids were published in Part XI11 1 and further constants for disubstituted benzoic acids are provided in the present paper. These acids comprise two series possessing a nitro-or chloro-substituent at the 2-position and a