F. W. Mar — Determination of Barium, etc. 



521 



Aet. LXV. — A Method for the Determination of Barium 

 in the presence of Calcium and Magnesium ; by F. "W. 

 Mar. 



[Contributions from the Kent Chemical Laboratory of Yale College — XIV.] 



The recent investigation* by Prof. R. Fresenins of the 

 value of the various methods which have been proposed for 

 the separation of barium and calcium, shows that but two of 

 the methods tested by him are sufficiently accurate for good 

 analytical work, and even with these it is necessary to make 

 two treatments in order to obtain a complete separation. The 

 method here described may therefore be of interest and by 

 reason of its rapidity and accuracy may prove valuable, although 

 since the publication of the work of Fresenins another methodf 

 has been published from this laboratory which, in point of 

 accuracy, leaves little to be desired. 



It has long been known that barium chloride is insoluble to 

 a marked degree in concentrated hydrochloric acid, but the 

 difficulty of filtering off the strong acid has in the past preven- 

 ted the determination of the exact amount of this insolubility, 

 and for the same reason the reaction has not been available for 

 quantitative use. Since the invention of the G-ooch crucible, 

 however, the treatment of such strong acid filtrates has become 

 a matter of the greatest ease, and it seemed worth while to 

 investigate the limits of the insolubility of barium chloride in 

 the strong acid and to ascertain whether the reaction might not 

 be of use in the separation of barium from calcium and mag- 

 nesium, the chlorides of which are soluble in the strong acid. 



The barium chloride used in the following experiments was 

 the pure crystallized chloride containing two molecules of 

 water. The calcium salt was the pure fused chloride, and the 

 magnesium salt was the pure crystallized magnesium chloride 

 dried at 50° C. As the two latter were not determined in the 

 experiments it was not necessary to know the composition of 

 the salts used as regards hygroscopic moisture. Attention was 

 first given to determining the solubility of barium chloride in 

 hydrochloric acid. 



Series A. 



Ex 



p. BaCU 



. 2H 2 



Water. 



HC1. 



Total filtrate. BaCl 2 





Loss. 



1 



0-5024 



grm. 



5 



cm 3 



20 



cm : 







4241 grm. 



0-0041 grm 



2 



0-5084 



cc 



5 



cc 



20 



cc 







0-4304 



cc 



0-0030 " 



3 



0-5099 



cc 



2 



cc 



25 



cc 







0-4320 



cc 



0-0027 " 



4 



0-5033 



cc 



2 



cc 



25 



cc 



90 



cm 3 



0-4251 



cc 



0-0039 " 



5 



0-5047 



cc 



2 



cc 



25 



cc 



52 



cc 



0-4247 



cc 



0-0055 " 



6 



0-5065 



cc 



2 



cc 



50 



cc 



115 



cc 



0-4257 



cc 



0-0060 " 



7 



0-5008 



cc 



2 



cc 



50 



cc 



75 



cc 



0-4218 



cc 



0-0051 " 



8 



0-5011 



. cc 



2 



cc 



50 



cc 



93 



cc 



0-4220 



cc 



0-0051 " 



9 



0-5024 



- cc 



2 



cc 



75 



cc 



3 23 



cc 



0-4246 



cc 



0-0037 " 



*Zeitschrift fiir anal. Chem., xxx, 595. 



f P. B. Browning, this Journal, vol. xliii, p. 314. 



