COPPER CHLORIDE. 175 



dehydrated by heating in a current of dry hydrochloric acid, at a tempera- 

 ture of from 140 to 150, to constant weight. The salt was then placed 

 in a vacuum desiccator over sulphuric acid and potassium hydroxide, to re- 

 move any traces of hydrochloric acid. The salt had a dark-brown color, 

 and gave perfectly clear solutions when dissolved in the water or the alcohols. 

 The salt was analyzed by the electrolytic method, using a rotating anode. 

 The results of the analysis agreed with the calculated result for pure copper 

 chloride to within 0.05 per cent. The salt was preserved in glass-stoppered 

 bottles over phosphorus pentoxide. 



The results obtained in the mixture of methyl alcohol and water were not 

 entirely satisfactory, because of the formation in the 50 per cent, and more 

 especially in the 75 per cent mixtures, of a cloudiness in the solutions within 

 a few minutes after dissolving the salt. This was probably due to a partial 

 reduction of the salt by the alcohol in the presence of water, since no such action 

 could be observed in either the methyl alcohol or the aqueous solutions. The 

 conductivity of the solutions in which the cloudiness appeared was deter- 

 mined without filtering the solution, and after 24 hours the conductivity of 

 the solution was again determined. No appreciable change in the conductiv- 

 ity could be detected, showing that the change in the solution proceeded rap- 

 idly at first and soon reached the equilibrium point. 



An attempt was made to determine the conductivity of copper chloride in 

 acetone, and mixtures of acetone with other solvents, but there was a very 

 appreciable action between the salt and the acetone, and, consequently, work 

 in this field was given up. There was not only a very rapid change in the con- 

 ductivity of the acetone solutions of copper chloride, so that it was impossible 

 to duplicate results ; but the molecular conductivity varied with the dilution 

 in a peculiar manner becoming greater with increase in dilution from N/100 

 to N/200, and then decreasing from N/200 to N/800, where the values reached 

 a minimum, and then increasing again from N/800 to N/1600. 



The solutions changed color slowly on standing for some time, and when 

 the solvent was distilled off on a water-bath apparently an organo-metallic 

 compound remained in the flask, which had none of the properties of either 

 cupric or cuprous chloride. 



Table 78, for copper chloride, in mixtures of methyl alcohol and water, when 

 plotted as curves (figs. 80 and 81), shows that there is a decided drop in the 

 curves below the rule of averages, and that this drop in the curve is most 

 pronounced in the 50 per cent mixtures. The values between 75 per cent 

 and 100 per cent mixtures are practically in accord with the rule of averages, 

 at 25, and have a general tendency in the same direction at 0. 



It is also to be observed that the values for the conductivity in methyl 

 alcohol are very much smaller than the corresponding values in water. 



