Hydrogen in Electrolytic Zinc. — By W. Roy Elliot, B. Sc, 



Dalhousie University, Halifax, N. S. 



(Read 18 Jan., 1926) 



Ralston, in a paper published recently in the Transactions 

 of the American Electrochemical Society', called attention to 

 the work of Schwarz on the hydrogen occluded by cathode 

 zinc. This amounts to 5-11 c. c. per gram, and is doubtless the 

 cause of the low specific gravity of electrolytic zinc. At the 

 time the advanced copy of Ralston's paper appeared I was 

 engaged on the study of the properties of zinc deposited under 

 various conditions. I have used some of my depostits to 

 determine the amount of hydrogen occluded as it seemed un- 

 likely that Schwarz' results, obtained by dissolving weighed 

 amounts of zinc in acid, could be exact. The quantities of 

 hydrogen found are about one-tenth those found by Schwarz. 

 In other respects my observations agree with Ralston's. 



The zinc was deposited on small aluminium cathodes 

 between lead anodes. The amount of zinc sulphate was kept 

 approximately constant by the addition of small amounts of 

 zinc oxide. The solutions were acid except at the beginning 

 of the experiment and no glue was used. The deposits, except 

 in the two cases mentioned in the table, were of good quality. 

 They were from 0.3-0.4 mm. thick. 



The volumes of the occluded gas^s were determined by 

 placing a weighed amount of the zinc in a pyrex tube, connected 

 to a Toepler pump by a mercury seal. The apparatus was 

 exhausted to 0.01 mm., and allowed to stand for some time 

 to see that no leak developed. The zinc was then melted by 

 a resistance furnace, and the gases were pumped off and mea- 

 sured. No quantitative analysis of the gas was made, but 

 qualitative tests showed it to be hydrogen. 



1.-47.193,(1925) 



