Gooch and Peters— Titration of Oxalic Acid. 465 



As Kessler has noted, a sufficiency of the manganous salt, 

 acting no doubt as the medium of transfer of oxygen, may 

 bring about interaction between the permanganate and the 

 oxalic acid at atmospheric temperatures without the tedious 

 delay ordinarily encountered in the attempt to consummate 

 that action in cold solutions. It would seem natural that the 

 manganic hydroxide formed in the Guyard reaction at low 

 temperatures should yield more readily to the reducing action 

 of the oxalic acid than the more anhydrous form to be expected 

 in hot solutions, so that at such temperatures the limits as to 

 proportions of manganous salt, acid, and dilution, within 

 which favorable action may take place, should be wider ; more- 

 over, the undesirable action of the permanganate upon hydro- 

 chloric acid, when that acid is present, should be less appreci- 

 able at lower temperatures. In our experiments, therefore, 

 upon the oxidation of oxalic acid by potassium permanganate 

 in presence of hydrochloric acid, we have studied the effect of 

 varying the proportions of the manganous salt both at atmos- 

 pheric temperatures and the higher temperatures generally 

 employed. 









Temperature 20 



°-26° a 

















Ammo- 











Number 



Volume 





HC1 



nium 









Variation 



of 



at begin- 



H 2 S0 4 



Sp. gr. 



oxalate 





MnS0 4 . 



MnCl 2 . 



from 



experi- 



ning of 



1: 1 



1-09. 



A^ 



KMn0 4 . 



5H 2 0. 



4H 2 0. 



standard. 



ment. 



titration. 



cm 3 . 



cm 3 . 



cm 3 . 



cm 3 . 



grams. 



grams. 



cm 3 . 



1 



130 





10 



25 



2390 



•0040 





+ 0-15 



2 



130 





10 



25 



23-90 



•0120 







+ 0-15 



3 



130 



.... 



10 



25 



23-80 



•0250 





+ 0-05 



4 



130 







10 



25 



23-75 



•0400 





+ 0-00 



5 



130 





10 



25 



23-76 



•0500 







+ 0-01 



6 



130 





10 



25 



23-70 



•1000 







— 0-05 



1 



130 







10 



25 



23-75 



•2000 







o-oo 



8 



130 







10 



25 



24-20 





•0200 



+ 0-45 



9 



130 





10 



25 



23-95 



_ _ _ _ 



•0200 



+ 0-20 



10 



130 



... 



10 



25 



23-80 







•0400 



+ 0-05 



11 



130 







20 



25 



23-75 







•0400 



o-oo 



12 



130 





30 



25 



23-75 







•0400 



o-oo 



13 



130 







10 



25 



23-75 



1-0000 







o-oo 



14 



130 





10 



25 



23-75 



2-0000 







000 



15 



130 







10 



25 



2375 



3-0000 





o-oo 



16 



130 



1 





25 



23-72 





1-0000 



—0-03 



17 



130 



1 







25 



23-74 





2-0000 



-001 



18 



130 



1 





25 



23-72 





3-0000 



-0-03 



19 



130 



2 





25 



23-70 





0-5000 



-0-05 



20 



130 



3 







25 



23-75 





05000 



000 



Temperature about 80°. 



21 



145 



10 



10 ; 



25 



2390 



0-5000 1 



+ 0-15 



22 



145 



10 



10 



25 



23-70 



1-0000 



-0-05 



23 



500 



10 



10 



25 



23-75 



1-0000 1 



000 



24 



500 





10 



25 



23-70 



1-0000 



-0-05 



25 



500 







10 



25 



24-10 



0-5000 



+ 0-35 



