Ionization of perchloric acid in aqueous solution. N.m.r. studies and further Raman investigations

Abstract

¹H and ³⁵Cl nuclear magnetic resonance measurements of chemical shifts in aqueous perchloric acid solution at 25° have been made and compared with previous data obtained by this method. Some additional Raman spectroscopic measurements on two less-intense bands of the perchlorate ion spectrum confirm earlier measurements on the 931 cm^–1 band. It is concluded from analysis of results from both methods of study that perchloric acid is completely ionized up to about 6 M. Above this concentration the acid is incompletely ionized, the degree of ionization is uncertain but is not lower than 90 % at 12 M. In an appendix the problem of the so-called “refractive index” corrections in Raman intensity measurements is discussed.