Gooch and Gilbert — Ammoaiiim Vanadate. 



209 



was connected, as shown in the figure, with the receiver charged 

 with a solution of 2*5 grms. of potassium iodide in boiled water, 

 and the apparatus was filled with carbon dioxide. The stop- 

 cock of A was closed, the bulb of A was charged with 50*^™^ of 

 strong hydrochloric acid, the connection with the carbon diox- 

 ide generator was again made, with care to displace all residual 

 air from the bulb. The acid was introduced into B by opening 

 the stopcock and, in a gentle current of carbon dioxide, the 

 heating was continued an hour after the development of color 

 in the receiver showed that bromine was coming over from the 



flask. The iodine set free in the receiver was titrated with 



sodium thiosulphate standardized against iodine of value known 



111 

 by comparison with — arsenious acid. The standard of the 



ammonium vanadate taken, as determined by the Holverscheit 

 method in its simple form, was found to be unchanged when 

 portions of the salt were treated according to the modification 

 necessitated by the presence of so much asbestos in the trial 

 tests, viz., in presence of more acid and in an atmosphere of 

 carbon dioxide. 



In this manner the determinations of the following table 

 were made : 





Table 



II. 







Standard 







4VO3 taken. 



NaaSoOs used. 



V2O5 found. 



Error. 



grams. 



cm^ 



^rams. 



grams. 



0-1000 



8-35 



0-0V60 



0-0001 — 



0-1000 



8-39 



0-0764 



0-0003 + 



0-1000 



8-38 



0-0763 



0-0002 + 



0-1000 



8-37 



0-0962 



0-0001 + 



0-1000 



8-32 



0-0757 



0-0004 — 



0-1000 



8-25 



0-0751 



0-0010 — 



0-1000 



8-36 



0-0761 



0-0000 



0-1000 



8-33 



0-0758 



0-0003 — 



