Vibrational spectral studies of solutions at elevated temperatures and pressures. VII. Raman spectra and dissociation of nitric acid

Abstract

An exploratory study of the Raman spectra of nitric acid solutions up to 250 °C has been undertaken. The decrease in the frequencies of the νN—(OH) and δNO2 bands of HNO3 as temperature and concentration increase have been interpreted in terms of the reduced strength of hydrogen bonding. Approximate values of the degree of dissociation α have been determined and show that nitric acid is a very much weaker acid at high temperatures.