236 Goocli and Edgar — Reduction of Vanadic Acid. 



tion and acts upon the permanganate sufficiently to use up 

 about 0*7 cm3 of that reagent, a deduction of that amount from 

 the total amount used was made for such action in each experi- 

 ment, before calculating the degree to which the vanadic acid 

 had been reduced. 



From these results it is plain that the degree in which 

 vanadic acid may be reduced by magnesium in the presence of 

 hydrochloric acid or sulphuric acid is irregular and dependent 

 upon conditions not easily controlled. With magnesium amal- 

 gam the reduction proceeds most readily and approximates 

 more or less to the condition of V 2 2 . 



It is obvious that under none of the conditions which we 

 have tried is the reduction by magnesium sufficiently definite 

 to be applied in a good analytical process. 



In Table II are given the results of the reduction of vanadic 



Table II. 



V 2 B V 2 5 Error 



taken as calculated in terms 

 Exp't ' NaV0 3 from oxidation of Remarks 



KM11O4 of V 2 2 V 2 5 



cm 3 grm. grrn. grm. 



A. 

 Reduced in flask with Zinc and Hydrochloric Acid 

 N/lOx 

 1-095 



1. 35-0 0-1235 0-1166 — 0-0069 ) Poured out into dish 



2. 35-85 0-1235 0-1194 — 0-0<>41 [ titrated in presence 



3. 34-9 0-1235 0-1163 —0-0072) of MnS0 4 



B. 



Eeduced in flask with Zinc and Sulphuric Acid 

 N/10 x 

 1-0956 



4. 36-3 0-1235 0-1203 —0*0032] 



5. 36-4 0-1235 0-1209 —0-0026 | T . , . , , 



6. 36-2 0-1235 0-1218 -0-0022 y iltratecl m tne reduc- 



7. 36-05 0-1235 01 206 —0-0029 | tlask. 



8. 36-1 0-1235 0-1201 —0-0034 J 



9. 35-68 0-1235 0-1188 -0-0047 I Po^d into dish for 



\ titration 



10. 34-8 0-1235 0-1159 -0-0076 i Ex P°^ d in dish 20 



\ minutes 



C. 

 Reduced by column of Amalgamated Zinc 



Titrated in the receiv- 

 er exposed to the air 





JM/lOx 

 1-052 









1. 



42-4 



0-1381 



0-1356 



— 0-0025 



2. 



42-7 



0-1381 



0-1366 



— H0015 



3. 



42-2 



0-1381 



0-1350 



— 0-0031 



4. 



42-5 



0-1381 



0-1359 



— 0-0022 



