Gooch and Gates — Decomposition of Hydrochloric Acid. 437 



five periods following the preliminary interval, the volumetric 

 ratios of oxygen to hydrogen were 0-247, 0*272, 0*285, 0-319. 

 Thereafter, in the remaining fifteen periods, the oxygen- 

 hydrogen ratios were nearly constant at an average of 0*332. 

 Practically the same average ratio (0-331) is recorded for 

 observations taken under varying conditions of current and 

 concentrations of hydrochloric acid in water; viz., a current 

 of 0*006 amp and 0*023 amp in a solution of 1-25 to 1000; 0*021 amp 

 and 0*250 amp in a solution of 5*3 to 1000 ; 0*020 amp and 0*100 amp 

 in a solution of 10'7 to 1000 ; and 0*053 amp in a solution of 55*8 

 to 1000. The conclusion was therefore drawn that the ratio of 

 the volumes of oxygen liberated at the anode to the volume of 

 hydrogen received at the cathode in the electrolysis of hydro- 

 chloric acid is constant and independent of the intensity of the 

 current and concentration of the solution ; and, inasmuch as a 

 subsequent experiment with a mercury cathode established a 

 closely concordant ratio, it was further concluded that the 

 ratio is, perhaps, also independent of the nature of the anode. 

 The ratio of the volume of hydrogen equivalent to the 

 liberated oxygen to the total volume of hydrogen taken as 

 unity, Doumer calls the "factor of ionization of water," and 

 this factor, 0*662 or about f , expresses the view that of the 

 hydrogen received at the cathode about f is derived from 

 water and -J from hydrochloric acid ; and that for every 

 molecule of hydrochloric acid electrolyzed one molecule 

 of water must also be electrolyzed, if water is ionized to 



2H and O, — or two molecules, if water is ionized to H or OH. 



A still later communication* deals with velocity of move- 

 ment of the chlorine and hydrogen ions. Upon the hypothesis 

 that two-thirds of the current is carried by the ions derived 

 from water and one-third by the ions derived from hydrochloric 

 acid, Doumer calculates that the loss of acid should be the same 

 at both electrodes. This was found to be the case in each of 

 three experiments made with a silver anode in weak solution 

 and with a feeble current. Doumer, therefore, summarizes 

 the results in the statement that (1) the ionization of water 

 interferes in active fashion in the electrolysis of solutions of 

 hydrochloric acid, and that (2) the speed of transfer of the ions 

 H and CI is practically the same. 



The earlier and very elaborate transfer expsriments by 

 Xoyes and Samraetf lead to precisely the same conclusion 

 as to the ionic velocities, provided it be assumed that two- 

 thirds of the current is carried through the solution by ions 

 derived from water. In these experiments, in which standard- 

 ized hydrochloric acid was electrolyzed between a platinum 

 *Compt. Kend., cxlvi, 894-896. f Jour. Amer. Cheni. Soc, xxiv, 949. 



