Sublimation pressures of solid solutions III. NH4Cl + NH4Br

Abstract

The total sublimation pressures of ammonium chloride, ammonium bromide, and of ten solid solutions of these salts, covering the entire composition range, have been measured by a static method from 250 to 320°C. The results were fitted to ln P = A - BT-1 + ClnT. The isothermal variation of total pressure with composition indicates that the solids deviate positively from Raoult's law. The differences between the "second-law" and "third-law" values for the enthalpy of sublimation for the pure chloride and pure bromide are discussed. Results are presented for the variation with composition, at 550 K, of the enthalpy of sublimation, uncorrected for possible incomplete dissociation in the gas phase. © 1971 Academic Press Inc. (London) Ltd. All rights reserved.