446 Gooch and Gates — Decomposition of Hydrochloric Acid. 



in the proportion of oxygen set free ; or, in general 

 terms, an eighty-fold increase in the current density involves, 

 in the average, a ten per cent increase in the oxygen ratio. 



It will be seen that the experimental results of which an 

 account has been given contravene Doumer's claim that the 

 ratio of the volumes of hydrogen and oxygen evolved in the 

 electrolysis of hydrochloric acid is constant and independent 

 of the strength of the current and concentration of the solution. 

 They afford, therefore, no basis for Doumer's calculation of 

 equal velocities for the hydrogen and chlorine ions. .Nor does 

 Doumer's discovery of equal acidity at the electrodes establish 

 such a relation of velocities ; for, if it be assumed that the cur- 

 rent is carried by the ions of hydrochloric acid we have 166*6, 

 according to Noyes and Sam met,* for the transfer number of 

 chlorine at a concentration at which the oxygen-hydrogen ratio 

 approximates Doumer's figure, - 332 ; and if it be further 

 assumed that the oxygen evolved is set free by the action of 

 transferred chlorine ions with simultaneous regeneration of 

 hydrochloric acid, the condition which produces the evolution 

 of oxygen corresponding to the oxygen-hydrogen ratio 0'332 

 must result in the production of equal acidity of the electrode 

 liquids. 



The observed phenomena afford, therefore, no criterion for 

 deciding how much of the oxygen liberated in the electrolysis 

 of hydrochloric acid under any given conditions is transferred 

 through the liquid and how much is evolved by the action of 

 transferred chlorine at the anode. 



* Log. cit. 



