Edgar — Estimation of Vanadic and Arsenic Acids. 301 

 Table (I). 



Taken 

 V 2 5 



Found 

 V 2 5 



Error 



v 2 o 5 



Taken 



As 2 5 



Found 

 As 2 5 



Error 

 As 2 5 



(I) 



N/10 



Iodine 



(II) 



N/10 

 Iodine 



grm. 



grm. 



grm. 



grm. 



grm. 



grm. 



cm 3 . 



cm 3 . 



0-1183 



0-1181 



— 0-0002 



0-0960 



0-0961 



+ 0-0001 



12-95 



29-65 



0-1183 



0-1183 



±0-0000 



0-0960 



0-0962 



+ 0-0002 



1297 



2970 



0-1183 



0-1182 



— o-oooi 



0-0960 



0-0962 



+ 0-0002 



12-96 



29-70 



00591 



0-0593 



+ 0-0002 



0-0480 



0-0480 



±0-0000 



6-50 



14-85 



0-0591 



0-0594 



+ 0-0003 



0-0480 



0-0482 



+ 0-0002 



6-52 



14-90 



0*0591 



0-0589 



— 0-0002 



0-0480 



0-0483 



+ 0-0003 



6-45 



14-86 



0-1774 



0-1779 



+ 0-0005 



0*1440 



0-1438 



— 0-0002 



19-50 



44-50 



0-1774 



0-1774 



±0-0000 



0-1440 



0*1440 



±0-0000 



19-45 



44-50 



0-1774 



0-1776 



+ 0-0002 



0-1440 



0-1442 



+ 0-0002 



19-47 



44-45 



0-2366 



0-2371 



+ 0*0005 



0-0480 



0-0478 



— 0-0002 



26-00 



34*31 



0-2366 



0-2366 



±0-0000 



0-0480 



0-0480 



±0-0000 



25-95 



34-30 



00591 



0-0593 



+ 0-0002 



0-1440 



0-1439 



—o-oooi 



6*50 



38-90 



Antimony and Vanadium. 



Since antimonic acid is reduced by sulphur dioxide on 

 heating in a pressure flask* there seemed no reason to suppose 

 that antimony and vanadium should not be determined in the 

 presence of each other by a process similar to the one used for 

 arsenic and vanadium. Accordingly a series of experiments 

 was made in which solutions containing vanadic acid and anti- 

 monic acid were treated in a manner exactly similar in detail 

 to the preceding. The results are given in Table (II). 



Taken 



Found 



s Error 



Table 

 Taken 



(II). 

 Found 



Error 



(I) 

 N/lOx 

 0-9375 



(II) 

 N/lOx 

 0-9375 



V 2 5 



v 2 o 5 



V.O5 



Sb 2 5 



Sb 2 5 



Sb 2 5 



Iodine 



Iodine 



grm. 



grm. 



grm. 



grm. 



grm. 



grm. 



cm 3 . 



cm 3 . 



0-1183 



0-1185 



+ 0-0002 



0-0757 



0-0759 



+ 0-0002 



13-85 



23-69 



0*1183 



0-1186 



+ 0-0003 



0-0757 



0-0764 



+ 0-0007 



13-87 



24-05 



0-1183 



0-1183 



±0-0000 



0-0757 



0-07G0 



+ 0-0003 



13-83 



23-95 



0-1774 



0-1777 



+ 0-0003 



0-1261 



0-1258 



— 0-0003 



20-80 



37-55 



0-1774 



0-1777 



+ 0-0003 



0-1261 



0-1258 



— 0-0003 



20*80 



37-55 



0-1774 



0-1773 



—o-oooi 



0-1261 



0-1260 



—o-oooi 



20-75 



37-50 



0-2366 



0-2376 



+ 0*0010 



0-1261 



0-1257 



— 0-0004 



27-80 



44-52 



0-2366 



0-2369 



+ 0-0003 



0-1261 



0-1263 



— 0-0002 



27-70 



44-50 



0-2366 



0-2369 



+ 0-0003 



0-1261 



0-1260 



—o-oooi 



27-70 



44*45 



Summary. 



In the preceding paper it has been shown that vanadic and 

 arsenic acids, or vanadic and antimonic acids, may be readily 

 determined in the presence of one another by a method based 

 upon the differential reducing action of tartaric or oxalic acid 

 and sulphur dioxide, the reoxidation being in each case effected 

 with iodine in alkaline solution under the conditions described 

 above. 



*VonKnorre : Zeitschr. angewandte Chem. 1888, 155. 



