The hydrogen fluoride solvent system. Part II. Cryoscopic measurements

The application of cryoscopy to the study of HF solutions is discussed and a suitable cryoscope is described. The freezing point of HF under its own vapour pressure was found to be –83·57 °C. The f.p. depression produced by dilute solutions of the binary electrolytes LiF, NaF, KF, and NH4F, and the non-electrolytes XeF2, HSO3F, SO2, and SF6, and S2O5F2 are reported. The experimental value of the cryoscopic constant was found to be 1·55 ± 0·05 °C mole–1 kg.