ESTIMATION OF SULPHATES. — CREIGHTON. 



209 



chloric acid, contained one grrm per litre ; or 1 cc. was equiva- 

 lent to one milligram of the metal. 



The precipitation of the sulphate was carried out at 100° C, 

 and the precipitate was allowed to digest in the hot (80 — 90° C.) 

 liquid for three or four hours before filtering. 



The results given in the following tables are the means of 

 three analyses. 



The experimental error in this work is ± 0.0008 grams. 



In the first table are given the results obtained bv adding 

 various amounts aluminium chloride solution to 50 cc. of 

 ammonium sulphate solution. 



Table 1. ' 



Volume of 



Ammonium 



Sulphate 



Solution used. 



Volume of 



Aluminium 



Chloride 



Solution used. 



Weight of 

 Barium 

 Sulphate 



Precipitate. 



Increase in 



Weight due to 



the presence of 



Aluminium. 



CC. 



cc. 



grams 



grams 



nO . GO 





0.86-49 

 0.8651 





50.00 



10.00 



0.0006 



50.00 



15.00 



0.8672 



0.0023 



50.00 



20.00 



0.8699 



0.0050 



50.00 



25.00 



0.8714 



0.0065 



50.00 



35.00 



0.8710 



0.0061 



50.00 



50.00 



0.8711 



0.0062 



The second table gives the results obtained by adding a 

 constant volume of aluminium chloride solution to diflerent 

 volumes of ammonium sulpliate solution. 



