Permanganate in the Presence of Ferric Chloride. 35 



From these results the conclusion may be drawn that the low 

 indications of the amount of permanganate apparently reduced 

 during digestion in the experiments recorded in Table I, at 

 least so far as concerns those experiments in which no ferric 

 chloride was used, were in all probability due to the oxidizing 

 action of the unexpelled chlorine on the oxalic acid, and that 

 the large variations in results were due to the greater or less 

 retention of the chlorine. In experiments XIII to XYIII it is 

 seen further that amounts of permanganate very much greater 

 than those used in Wagner's experiments and in the experi- 

 ments of Table I above can be reduced by the same amount 

 of hydrochloric acid, and under the same conditions of tempera- 

 ture and time as in those other experiments ; for, in these last 

 experiments, also, the permanganate color entirely disappeared 

 during the, digestion. 



In order to ascertain if a current of air is equally as effective 

 in removing the chlorine as is carbon dioxide, and also because 

 of the greater availability of the former, the experiments 

 recorded in Table III were conducted in a manner identical with 

 those of Table II, except that a current of air dried and puri- 

 fied was substituted for the carbon dioxide. When also the 

 success of the air current was apparent, ferric chloride was 

 again used and the effect noted. 



Results are outlined in the following table. 



Table III. 



N 

 [9-90 cra3 approximately — H 2 C 2 4 = 20'09 cm3 KMn0 4 .J 

























KMnO 

















Residual 









appar- 











KMn0 4 



Tem- 



Time 



KMn0 4 



Cl 





KMn0 4 



ently 





* HC1 



^-HCl 



=- FeCl 3 



before 



pera- 



of 



color 



Test 



H2C2O4 



to 



reduced 







10 ^ 





diges- 



ture. 



diges- 



after 



after 



cm 3 . 



color. 



during 





cm 3 . 



cm 3 . 



cm 3 . 



tion. 

 cm 3 . 



C°. 



tion, 

 min. 



diges- 

 tion. 



diges- 

 tion. 





cm 3 . 



diges- 

 tion. 

 cm 3 . 



I 



100 



9-90 





9-90 



50 



60 



none 



none 



990 



18-88 



8-69 



II 



100 



9-90 





9-90 



" 



a 



" 



a 



9-90 



18-87 



8-68 



III 



100 



9-90 



'_'/_ 



9-90 



a 



a 



a 



a 



9-90 



18-80 



8-61 



IV 



100 



9-90 





9-90 



a 



a 



a 



a 



9-90 



18-81 



8-62 



V 



100 



9-90 





9-90 



a 



(i 



a 



a 



9-90 



18-80 



8-61 



VI 



100 



9-90 





9-90 



a 



it 



" 



a 



9-90 



18-82 



8-63 



VII 



100 



9-90 





9 90 



a 



30 



" 



a 



9-90 



18-77 



8-58 



VIII 



100 



9-90 







9-90 



a 



n 



i i 



doubtful 



9-90 



18-70 



8-51 



IX 



100 



9-90 







990 



a 



15 



a 



very 

 faint 



9<90 



18-70 



8-51 



X 



100 



9-90 



... 



9-90 



a 



a 



a 



a 



9-90 



18-68 



8-49 



XI 



100 





9-90 



9-90 



a 



60 



a 



none 



9-90 



18-87 



8-68 



XII 



100 





9-90 



9-90 



1 1 



a 



a ■ 



4 < 



9-90 



18-85 



8-66 



XIII 



100 





9-90 



9-90 



11 



a 



a 



a 



9-90 



18-81 



8-62 



XIV 



100 





9-90 



9-90 



a 



i i 



'•' 



a 



9-90 



18-81 



8-62 



XV 



100 





9-90 



9-90 



a 



it 



a 



a 



9-90 



18-87 



8-68 



XVI 



100 





9-90 



9-90 



a 



u 



a 



a 



9-90 



18-85 



8-66 



XVII 



100 





9-90 



9-90 



a 



30 



*< 



" 



9-90 



18-80 



8-61 



XVIII 



100 







9-90 



9-90 



a 



(< 



a 



doubtful 



9'90 



18-72 



8-53 



XIX 



100 







9-90 



9-90 



a 



15 



" 



very 

 faint 



9-90 



18-65 



8-46 



XX 



100 







990 



9-90 



n 



n 



a 



(< 



9-90 



18-67 



8-48 



