RICHARDS AND STULL. BROMINE AND OXALIC ACID. 



825 



II. The Effect of Varying the Concentration 

 of Oxalic Acid. 



In the following series of experiments the weight of oxalic acid present 

 varied from 0.0587 gram to 4.112 grams in 63.3 cubic centimeters, while 

 the same amount of bromine (0.1601 gram) was originally present in 

 each case. The time of the reaction in each case was 60 minutes. 



SERIES II. 



The most evident feature of these results is the fact that the speed of 

 reaction does not increase indefinitely with increasing concentration, but 

 that above a point corresponding to about three per cent of oxalic acid 

 by weight, the speed decreases. For a considerable space, between con- 

 centrations containing 0.7 per cent to 4 per cent of oxalic acid, the speed 

 scarcely changes. 



Kohlrausch and Holborn * state that the specific conductivity of a 3.5 

 per cent solution of oxalic acid is 508 (10k 4 18 ), while a 7 per cent 

 solution has a conductivity of 783. The comparison of these data with 



* Leitvermugen der Electrolyte, p. 157 (1898). 



