38 Brown — Hydrochloric Acid, etc. 



were made to ascertain if possible how much permanganate can 

 be destroyed by the amount of hydrochloric acid used in the 

 experiments of Table I, II, and III, under the same conditions 

 of time and temperature, and also during greater periods of 

 time. It will readily be seen from the evident oxidation of 

 oxalic acid by chlorine in previous experiments that an exact 

 measure of the maximum amount of permanganate reduc- 

 tion during a given period of time can be obtained only 

 when all the chlorine is removed and at the same time the per- 

 manganate color just disappears — a condition difficult to attain. 

 The results recorded in Table IV should therefore be regarded 

 as approximate only. 



Thus it may be seen that the same amount of hydrochloric 

 acid as was used in the experiments of Table I, II, and III is 

 capable of breaking down approximately thirty times as much 

 permanganate as was used in those experiments and in the experi- 

 ments of Wagner, conditions of time and temperature being the 

 same. Changes of volume are of course involved in the use of 

 varying amounts of permanganate but an increase in volume 

 would in all probability be attended by a decrease in the relative 

 amount of permanganate reduced by a constant quantity of 

 hydrochloric acid. In any case the results show a more exten- 

 sive reduction than is indicated in Wagner's experiments and in 

 those of Tables 1, II, and III above. 



The conclusion must be drawn, then, that Wagner's experi- 

 ments in no way show the catalytic effect of ferric chloride in 

 the interaction between hydrochloric acid and potassium per- 

 manganate, nor do they furnish evidence in support of the 

 assumed formation of chlor-ferrous acid. They afford simply 

 an indication of the greater or less retention of chlorine in 

 solution, and the greater or less oxidizing action of this chlorine 

 on the oxalic acid in the presence or absence of ferric chloride. 



The author is indebted to Prof. F. A. Gooch for much advice 

 and assistance in the preparation of this paper. 



