Gooch and Gates — Decomposition of Hydrochloric Acid. 445 



In this experiment the ratio of oxygen to hydrogen was 

 fairly constant throughout the entire period of electrolysis 

 and higher by about thirty per cent than Doumer's ratio and the 

 maximum obtained at the lowest previous concentration of the 

 solution. It is interesting to note, moreover, that the 91*2 cm3 of 

 hydrogen evolved in the two-hour runs is the equivalent of 

 about 0*276 grm. of hydrochloric acid, or of nearly twenty 

 times the 0*014 grm. of acid originally contained in the 330 cm3 

 of solution. If all the hydrogen was derived from the primary 

 electrolysis of hydrochloric acid, an amount of the latter equal 

 to nearly twenty times that originally present must have been 

 electrolyzed and regenerated in the course of the experiment. 



The details of similar experiments with platinum electrodes 

 of different areas and in solutions of still lower concentrations 

 are given in summary in the following table. In A are given 

 the results obtained at various concentrations with an anode of 

 small area, while in B are given the results obtained with an 

 anode surface eighty times as large. 







Table V. 



— Anode 



of Platinum. 







Time 

 min. 



Cur- 

 rent 

 amp. 



ND 100 

 amp. 



Poten- 

 tial 

 volt* 



Concen- 

 tration: 



parts 

 in 



1000 



Hydro- 

 gen 

 cm 3 



Oxy- 

 gen 

 cm 3 



Eatio 

 of 

 Oxygen 

 to Hy- 

 drogen 



Mean 

 for 

 each 

 concen- 

 tration 









Anode Area= 



l-25cm3 









30 



0*05 



4*0 



23*4 



0172 



14-6 



5-7 



•390 







30 



0*10 



8*0 



85*7 







24-2 



9*9 



•409 



•399 



30 



0*05 



4-0 



97*2 



0*086 



11-0 



5*0 



•454 







30 



0*10 



8*0 



87-3 



_ _ . - 



24*7 



J 1*1 



•468 



•461 



30 



0*05 



4-0 



95*2 



0*043 



12*2 



5-4 



•442 



•442 



30 



0*039 



3*12 



98*7 



0*0086 



8*6 



4*1 



•477 



•477 









Anode Area= 



100 cm2 









30 



0*10 



0*10 



86*7 



0172 



24-0 



9*1 



•379 





30 



0*05 



0-05 



95*8 



0-086 



12*8 



5-2 



•406 







30 



0*05 



0*05 



92-8 



0*093 



11-6 



4-7 



•405 







30 



0*031 



0*031 



95-8 



0-0086 



8-8 



3-7 



•420 







The experiments of each series confirm in a general way the 

 former evidence to the effect that the proportion of oxygen 

 liberated increases as the concentration of the solution decreases. 

 The highest ratio of oxygen to hydrogen, found at the lowest 

 concentration, 0*0086 parts in one thousand, and at the high 

 current intensity, is within five per cent of what it would 

 be were water the primary and sole electrolyte. A compari- 

 son of the two series shows that a very large increase 

 in area of the anode is attended with some decrease 



Am. JottPv. Sci.— Fourth Series, Vol. XXVIII, No. 167.— November, 1909. 

 30 



