46 



WORK OF C. M. STINE. 



tions we have the difference in the hydrating power of the ions and molecules affect- 

 ing the total amount of water eliminated as water of hydration. Consequently, 

 where the total amount of salt is constant, but a change in the dissociation is pro- 

 duced, if the number of ions is large relative to the number of molecules undissociated, 

 as is the case in the more dilute solutions, the curve for D m does not at once show the 

 influence of diminishing the amount of solvent present. This phenomenon is brought 

 out by the curves as change of direction, or as increased curvature in the curve which 

 represents the value of D m . 



FERRIC CHLORIDE AND ALUMINIUM CHLORIDE. 



A pair of quaternary electrolytes was next studied. Ferric chloride and aluminium 

 chloride were employed. Very concentrated mother-solutions were prepared, and 

 the necessary measurements were made as quickly as possible, in order to reduce 

 hydrolysis to a minimum, there being an appreciable time factor in the hydrolysis of 

 such compounds as ferric chloride. Notwithstanding all precautions there was, of 

 course, considerable hydrolysis. Especially was this the case in the mixture of the 

 two salts, the presence of the aluminium chloride appearing to act catalytically upon 

 the solution of ferric chloride, causing a gradual precipitation of ferric hydroxide. 



It was necessary to extrapolate the value 84.6, since the solution failed to freeze 

 in the freezing mixture employed, i. e., solid carbon dioxide and alcohol. The more 

 concentrated solutions became so viscous when cooled down that it was difficult to 

 stir them properly. 



Table 33. Aluminium Chloride Data for Freezing-point and Conductivity Measurements, 



Weight-normal Corrections, and Hydrates. 



