Edgar — Estimation of Chromic and Vanadic Acids. 335 









(I) 



(II) 











v 2 o 5 



Cr0 3 



Na 3 S a 8 



Na 2 S 2 O s 





Error 



Error 



No. 



taken 



taken 









on 



on 



of 



as 



as 



ItylOx 1-031 



N/10 x 1-031 



v 2 o 5 



Cr0 3 



Expt. 



NaV0 3 



K 2 Cr 2 7 















gmi. 



grm. 



cm 3 



cm 3 





grm. 



grm. 



( 1) 



0-1523 







16.20 



16-22 



CD] 

 (H) 1 



±0-0000 

 + 0-0002 



---- 



(2) 



0*1523 







16-19 



16-20 



(I)j 

 (H)1 



—o-oooi 



±0-0000 



---,- 



( 3) 



02031 







21-59 



21-58 



(1)1 

 (H) 



-o-oooi 



— 0-0002 







( 4) 



0-1523 



0-0685 



36-08 



16-22 





+ 0-0002 



—o-oooi 



(5) 



0-1523 



0-0685 



36-10 



]6-20 





±0-0000 



±0-0000 



( 6) 



0*1523 



0-0085 



36-12 



16-17 





— 0-0003 



+ 0-0002 



( *) 



( 8) 



01523 



0-0685 



36-07 



16-20 





±0-0000 



—o-oooi 



0-1523 



0-1370 



56-00 



16-17 





— 0-0003 



+ 0-0001 



( 9) 



0-1523 



0-1370 



56-02 



16*22 





+ 0-0002 



±0-0000 



(10) 



0']523 



0-1370 



56-03 



16-19 





—o-oooi 



+ 0-0001 









N/10 x 0-992 



N/lO x 0*992 — Changed Stand, of Na 2 S 2 3 



(11) 



0-2031 



0-1370 



63-82 



22-46 





±0-0000 



—o-oooi 



(12) 



0*2031 



0-1370 



63-80 



22-48 





+ 0-0002 



— 0-0003 



(13) 



0-1016 



0-0685 



32-00 



11-25 





+ 0-0002 



+ 0-0001 



(14) 



0-1016 



0-0685 



31-92 



11-24 





+ 0-0001 



— o-oooi 



(15) 



0-1016 



0-0685 



31-90 



11-25 





+ 0-0002 



— 0-0002 



(16) 



0-0508 



0-0343 



15-95 



5-63 





+ 0-0002 



—o-oooi 



(17) 



0*0508 



0-0343 



15-95 



5-62 





+ 0-0001 



—o-oooi 



Alkaline potassium iodide was again placed in the absorption 

 apparatus and the latter connected with the Yoit flask. The 

 current of hydrogen was turned on and, after all air had been 

 expelled, the apparatus was disconnected momentarily, one or 

 two grams of potassium iodide were added to the solution in 

 the Yoit flask, and connections made again. Through the 

 separatory funnel ten to fifteen cubic centimeters of concen- 

 trated hydrochloric acid and three cubic centimeters of syrupy 

 phosphoric acid were added and the solution in the reduction 

 flask was boiled to a volume of ten to twelve cubic centime- 

 ters. The absorption apparatus was removed and cooled, 

 hydrochloric acid was added and the liberated iodine titrated 

 with approximately N/10 sodium thiosulphate. The results 

 of this titration are given under II, Table I. It is evident 

 that the iodine determined in the first titration corresponds to 

 reduction of the chromic and vanadic acids corresponding to 

 the equation, 



Y 2 5 + 2Cr0 3 + 8HBr= Y 2 4 + O 2 3 + 81 + 4H 2 

 while in the second case the iodine corresponds to a reduction 



