A METHOD FOR THE DETERMINATION OF HYDRI- 
ODIC AND HYDROBROMIC ACIDS. 
BY W. S. HENDRIX80N. 
About a year ago I presented to the Iowa Academy of 
Sciences a paper on a method of determining chloric acid 
by the reduction of the acid with metallic iron in the 
presence of dilute sulphuric acid, and the titration of the 
hydrochloric acid formed, by the method of Yolhard. 
The same paper, somewhat extended, appeared in another 
periodical.* In this communication it was suggested that 
the method might probably be used equally well for the 
determination of bromic and iodic acids, and two deter- 
minations of bromic acid were included in the paper. 
Early in the present academic year the study of the 
action of metallic iron on bromic and iodic acids, with a 
view to the determination of the acids, was taken up with 
the results that follow in this paper. 
Of course there could be little doubt that iron in acid 
solution would completely reduce both these acids giving 
their equivalents in hydrobromic and hydriodic acids, but 
since these are both strong reducing agents, they might be 
expected as soon as formed to react with the iodic and 
bromic acids remaining, with the liberation of six equiva- 
lents of bromine or iodine, according to well known reac- 
tions. The question to be settled really was, whether the 
iodine and bromine thus liberated would be readily changed 
at low temperature to the corresponding hydriodic and 
hydrobromic acids, so as to avoid any loss of iodine or 
bromine by volatilization. 
* American Chemical Journal, Vol. 3i3, p. 242. 
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