STUDY OF HYDRATION AND IONIZATION OF NITRIC-ACID IN BENZENE

The hydration and ionization of nitric acid in benzene were examined at 298 K. The distribution of nitric acid and of water between aqueous solutions and benzene were determined as functions of water activity in the aqueous phase. Two hydrates, mono- and decahydrate, were found in addition to the anhydride in the organic phase by analyzing the distribution data on the basis of the stoichiometry of the acid hydration. The mono- and decahydrate were ascribed to molecular and ionized nitric acid, respectively, by means of spectrophotometry of the organic phase. By the analyses of the absorption spectra and the distribution data, the ionization of nitric acid by water in benzene was clarified and the equilibrium constant was determined.