Barium from Strontium by Amy I Alcohol. 



461 



Several methods of treatment were followed to prevent if 

 possible this solubility, such as the addition of a few drops 

 of hydrobromic acid before boiling, of the same after the 

 barium bromide had separated, of a few drops of ethylene di- 

 bromide or ethyl bromide at the completion of the boiling, 

 of a few drops of bromine water before boiling, etc. The 

 results of these experiments showed these modifications to be 

 of little or no value. 



On boiling the strontium bromide with the alcohol slight 

 spots separated occasionally, which on the addition of a drop 

 of hydrobromic acid went into solution and did not appear on 

 re-boiling. In order to determine the solubility of the stron- 

 tium bromide in the alcohol a saturated solution was obtained 

 by boiling an excess of the strontium salt with the alcohol, the 

 salt in a measured portion of 10 cm 3 was precipitated as sul- 

 phate by the addition of ethyl alcohol, and sulphuric acid, and 

 weighed. Duplicate determination showed the solubility to 

 be about 0*2 gram on the oxide in 10 cm 3 of the alcohol. The 

 mode of procedure for the separation of these elements was 

 identical with that already described in the case of barium alone 

 up to the point at which the barium was filtered off, except, of 

 course, the addition at first of a measured and weighed amount 

 of a previously standardized solution of strontium bromide. 

 The strontium was precipitated from the filtrate as sulphate by 

 dilute sulphuric acid, ethyl alcohol being added to secure 

 thorough mixture. These precipitates were generally filtered 

 off upon asbestos felts, and, although their gelatinous character 

 delayed the filtration somewhat, the drying and burning of a 

 filter paper with the possible danger of loss by reduction in 

 the presence of burning paper was avoided. Series II gives 

 the results of a single treatment, and it will be seen that there 

 is apparently a slight contamination of the barium by the 

 strontium which where the latter is present in large quantities 

 balances the solubility of the barium (0*0013 grm. on the oxide.) 

 Where the amounts of strontium taken are small the loss of 

 barium due to solubility appears. 



Series II. 



BaO taken. 



BaO found. 



Error. 



SrO taken. 



SrO found. 



Error. 





grm. 



grm. 



grm. 



grm. 



grm. 



grm. 



(1) 



0-1228 



0-1225 



0-0003 — 



0-1070 



0-1065 



0-0005 — 



(2) 



0-1227 



0-1231 



0-0004 + 



0-1074 



0-1069 



0-0005 — 



(3) 



0-1224 



0-1228 



0-0004 + 



0-1070 



0-1067 



0-0003 — 



(4) 



0-1217 



0-1201 



0-0016 — 



0-0364 



0-0372 



0-0008 + 



(5) 



0-1216 



0-1222 



0-0006 + 



0-0133 



0-1124 



0-0009 — 



(6) 



0-0974 



0-0970 



0-0004 — 



0-0719 



0-0721 



0-0002 + 



(7) 



0-0971 



0-0973 



0-0002 + 



0-0730 



0-0727 



0-0003 — 



(8) 



0-0970 



0-0971 



0-0001 + 



0-0718 



0-0716 



0-0002 — 



(9) 



0-0411 



0-0390 



0-0021 — 



0-0365 



00385 



0-0020 + 



(10) 



0-0243 



0-0234 



0-0009 — 



0-1072 



0-1072 



o-oooo 



