46 Gooch and Curtis — Halogen Acids upon Vanadic Acid. 



Table III. ', 



Exp, 



10 

 11 

 12 

 13 

 14 

 15 

 16 

 17 

 18 



V 2 4 in 



0-1000 gm. 



NH4VO3 



taken 



gm. 



0-0699 

 0-0699 

 0-0699 

 0-0699 

 0-0699 

 0-0699 

 0-0699 

 0-0699 

 0-0699 



0-0699 

 0-0699 

 0-0699 

 0699 

 0-0699 

 0-0699 

 0-0699 

 0-0699 

 0-0699 



KI 



H 2 S0 4 





1 :1 



gm. 



cm 3 . 



1 



10 



1 



10 



1 



10 



1 



10 



1 



10 



1 



10 



1 



10 



1 



10 



•6 



6 



1 



10 



1 



6 



1 



10 



1 



10 



•6 



4 



•6 



10 



•6 



6 



•6 



6 



•6 



4 



Initial 

 vol. 

 cm 3 . 



50 

 45 

 50 

 60 

 55 

 55 



55 



55 

 80 

 75 

 55 

 55 

 55 

 55 

 55 



Final 

 vol. 

 cm 3 . 



35 

 35 

 35 

 35 

 35 

 35 

 35 

 35 

 35 



B 



35 

 35 

 35 

 35 

 35 

 35 

 35 

 35 

 35 



Eeduction flask 

 V 2 4 



Found 

 gm. 



0668 

 0-0692 

 0-0686 

 0-0696 

 0-0678 

 0-0690 

 0681 

 0-0689 

 0-0679 



0-0699 

 0-0713 



d-bVib 



0-0701 

 0-0717 

 0-0706 

 0-0703 

 00700 



Error 



0-0031- 

 00007- 

 0-0013- 

 0-0003- 

 0-0021- 

 0-0009- 

 0-0018- 

 0-0010- 

 0-0020- 



0-0000 ± 

 0-0014 + 



0-0011 + 

 0-0002 + 

 0-0018 + 

 0-0007 + 

 0-0004 + 

 0-0001 + 



Eeceiver V 2 4 



Found 

 gm. 



•0700 

 •0715 



•0718 

 •0744 

 •0704 

 •0710 



•0738 

 •0724 



•0722 



•0713 

 •0722 

 •0725 

 •0718 

 •0709 

 •0745 

 •0734 

 •0727 

 •0731 



Error 

 gm. 



0-0001 + 

 0-0016 + 

 0-0019 + 

 0-0045 4- 

 0-0005 + 

 0-0011 + 

 0-0039 + 

 0-0025 + 

 0-0023 + 



0-0014 + 

 0-0023 + 

 0-0026 + 

 0-0019 + 

 0-0010 + 

 0-0046 + 

 0-0035 + 

 0-0028 + 

 0-0032 + 



the residue in the reduction flask, in which the iodine was 

 added before the bicarbonate — the over-reduction in the residues 

 of section B averaging 0*0007 gm. The determinations of 

 reduction in the residue, in the series of section A, in which 

 the neutralization took place before the addition of the iodine, 

 uniformly show an incomplete reduction — amounting in the 

 average to 0*0015 gm. — an effect which is without doubt due 

 to the action of air upon the sensitive alkaline solution of the 

 reduced vanadate. 



It appears, thus, that under conditions of concentration in 

 which in absence of the vanadic acid there is no tendency 

 (barring the insignificant action of dissolved air) toward lib- 

 erating iodine, a little more iodine is liberated by vanadic acid 

 when acted upon by sulphuric acid and potassium iodide than 

 would correspond to a reduction of vanadic acid to the condition 

 of the tetroxide. 



Concerning the action of concentrated hydrochloric acid 

 and potassium iodide upon a vanadate, Friedheim and Euler* 

 give analytical data which go to show that reduction of the 

 vanadic acid goes nearly (97.2 per cent) to the condition 

 of the trioxide V 2 3 , and venture the assertion that the 

 incompleteness of the reaction is conditioned by the formation 

 of an oxyiodide which is broken up by the hydrochloric acid 



* Ber. Dtsch. chem. Ges., xxviii, 2071. 



