46 



F. B. Ilavens — Further Separations of 



acid to dissolve it. The beaker was then cooled by immersion 

 in an inverted bell-jar supplied with running water by means 

 of inlet and outlet tubes, and a current of gaseous hydrochloric 

 acid (generated by the gradual addition of sulphuric acid to a 

 mixture of hydrochloric acid and salt) passed through the 

 solution in the beaker to complete saturation. Ether was added 

 in volume equal to that of the original solution, and the 

 whole again saturated with hydrochloric acid gas. The crys- 

 talline chloride precipitated was caught on asbestos in a 

 filter crucible, washed with a previously prepared solution of 

 equal parts of ether and hydrochloric acid, saturated with hydro- 

 chloric acid gas, dried for half an hour at 150°-180° C, covered 

 with a layer of pure mercury oxide, heated gently over a low 

 flame under a ventilating hood, ignited over the blast, and 

 weighed as the oxide. The results show that aluminum can be 

 determined with reasonable accuracy in the presence of a pure 

 zinc salt. 



Table I. 



A1 2 3 

















taken as 



A1 2 3 





ZnO 



ZnO 





Error 



Final 



the chloride. 



found. 



Error. 



taken. 



found. 



Error. 



corrected. 



vol. 



grm. 



grm. 



grm. 



grm. 



grm. 



grm. 



grm. 



cm 3 . 



(1) 0-0562 



0-0562 



o-oooo 



OHIO 









._ 



(2) 00580 



00577 



0-0003- 



0-1034 















._ 



(3) .... 











0-1019 



0-1016 



0-0003 — 









(4) .... 











0-10)0 



0-1007 



0-0003- 







__ 



(5) .___ 











01100 



01095 



0-0005- 









(6) 00572 



0-0572 



o-o'o'oo 



0-1014 



0'1027 



0*0013 + 



00007- 



12 



(7) 0-0563 



00550 



0-0013- 



0-1026 



0-1038 



0-0012 + 



0-0008- 



16 



(8) 0-0577 



00576 



o-oooi — 



o-iooo 



01014 



0-0014 + 



0-0006— 



16 



(9) 0-0559 



0-0558 



o-oooi- 



0-1020 



0-1035 



0-0015 + 



0-0005 — 



16 



(10) 0-0563 



0-0556 



0-0007- 



0-2024 



0-2046 



0-0022 + 



0-0002 + 



20 



(11) 0-1111 



0-1107 



0-0004- 



0-2092 



0-2116 



0-0024 + 



0-0004 + 



20 



The zinc can be determined, after the evaporation of the 

 strong acid filtrate, by any of the well known methods. It was 

 found, however, that after thorough conversion to the nitrate 

 by repeated evaporation with nitric acid the salt could be ignited 

 directly to the oxide with satisfactory results. This is shown 

 clearly in Table I, exps. (3) to (5). In experiments (3) and (4), 

 zinc oxide was dissolved in nitric acid and the nitrate ignited 

 again to the oxide. In experiment (5), the zinc oxide was first 

 dissolved in hydrochloric acid and the chloride thus obtained 

 was converted to the nitrate by evaporating the solution (5 cm3 ) 

 with nitric acid (2 cm3 ), treating the residue with nitric acid (2 cm3 ) 

 and evaporating to dryness. 



In Table I (exps. 6-11) are given the results of experiments 

 in which both the aluminum and zinc were determined, — the 

 former, as described, by precipitating as the hydrous chloride 

 and weighing as the oxide, and the latter by carefully evapora- 

 ting the strongly acid filtrate (best with a small current of air 



