Gooch and Curtis— Halogen Acids upon Vanadic Acid. 47 



only at a concentration (volume) which can not be reached 

 without danger to the retort in which the operation is conducted. 

 Friedheim and Euler propose the addition of phosphoric acid 

 to this end and give excellent analytical results to sustain the 

 suggestion. 



In the experiments of the following tables, made in the 

 apparatus figured and described above, the reductions were 









Table IV. 











V 2 Oo in 















Exp. 



0-1000 NH4VO3 

 taken 



HC1 



KI 



Initial 

 vol. 



Final 

 vol. 



v 2 o : 



found 



cone. 









gm. 



cm 3 . 



gm. 



cm 3 . 



cm 3 . 



Flask 



Receiver 









A 











1 



0-0632 



5 



0-6 



50 



-* 





0-0323 











__ 



2 



: 0~613 



00627 



"i 



: 0"63~2 



5 



1 



55 



* 







0-0327 













2 



0-0618 



0-0637 



8 



: 0~63~2 



12 : 5 



1 



50 



* 





0-0378 







_ _ 



__ 





2 



: 0~6~15 



0644 



4 



: 0~632 



15 



1 



45 



* 





0-0372 







- — 



. 





2 



: 0~6~17 



0-0642 



5 



0632 



25 



1 



50 



* 





0-0518 



-- 







-- 



-- 



-- 



2 



: 0"6"l8 



0-0657 



1 



0-0632 



15 



B 

 1 



16 



2 



0-0618 



0-0630 



2 



0-0632 





_ _ 







0-0612 



0-0627 



3 



0-0632 







-. - 



_ _ 



__ 



0-0617 



0-0625 



4 



0-0632 



__ 





_ _ 



.. 



0-0620 



0-0630 



5 



0-0632 



.. 



_. 







0-0616 



0-0627 



6 



0-0632 











0-0618 



0-0628 



7 



0-0632 





_ _ 







0-0617 



0-0630 



8 



0-0632 







._ 





0-0617 



00629 



9 



0-0632 





_ _ 



_. 



._ 



0-0616 



0-0629 



10 



0-0632 



-- 



-- 



-- 



-- 



0-0618 



0-0630 



made by the action of hydrochloric acid and potassium iodide. In 

 series A varying concentrations were employed and the boiling 

 was interrupted as soon as the vapor of iodine had disappeared 

 from the flask and the contents of the receiver titrated with- 

 out admitting air. The receiver was then replaced, the 

 boiling continued until the volume remaining was about 2 cm3 , 

 when the free iodine in the receiver and the reduced product 

 in the flask were determined. In series B the boiling was 

 carried at once to the final stage. 



From these results it is apparent that the degree to which 

 vanadic acid may be reduced by hydrochloric and hydriodic 

 acids turns upon the concentrations. We have found no diffi- 

 culty in carrying the reduction, in the apparatus described, to 



* To the point when the vapor of iodine had disappeared from the flask — 

 approximately 40 cm3 . 



