JOURNAL 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. Ill OCTOBER 4, 1913 No. 16 



CHEMISTRY. The electrolytic reduction of iron for analysis. 

 J. C. HosTETTER. Geophysical Laboratory. Communicated 

 by A. L. Day. 



In the view of the ease with which reductions can be carried 

 out electrolytically, it is surprising that this subject should have 

 been so neglected in the field of analytical chemistry. The electro- 

 lytic reduction of iron for subsequent titration seems to have 

 attracted little attention. ^ W.th other ends in view, ferric salts 

 have often been reduced by this means. 



This method has been investigated to some extent by the writer 

 for the specific purpose of subsequent titration, and has been em- 

 ployed by him at intervals during the past year. Since the method 

 is entirely practicable and occasionally very desirable, it may not 

 be amiss to call attention to the conditions to be controlled when 

 this method is used for analytical purposes and to indicate the 

 degree of accuracy of which it is capable. 



The optimum conditions for complete reduction are primarily 

 those which lessen the formation of oxidizing compounds by the 

 current. The most suitable electrolyte for this particular prob- 

 lem is dilute sulfuric acid. The temperature during electrolysis 

 should be above 60°C. and the current density low. These con- 

 dition s^ are unfavorable to the formation of both hydrogen per- 



1 The only work hitherto undertaken from this viewpoint which has come to 

 the attention of the writer, is a paper offered by H. C. Allen at the Rochester 

 meeting of the American Chemical Society (Sept., 1913). The paper was read by 

 title only and appears not to have been published. 



2 For discussion of these conditions see Gmelin-Kraut Handb. d. anorg. Ch., 

 7th Auf., Bd. I, Abt. 1, 128, 558. 



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