ACTION OF BROMIC ACID ON METALS. 
BY W. S. HENDRIXSOX. 
About two years ago I submitted to the Iowa Academy of Science* 
a communication on the action of chloric acid on metals, in which it 
was shown that in some cases the metals dissolved without the evolution 
of any gas, the action apparently being the oxidation of the metal and 
the immediate formation of salts from the oxides and the excess of 
chloric acid, and the hydrochloric acid produced by the reduction of 
chloric acid. In the cases of some metals there occurred at the same 
time oxidation of the metal and the evolution of free hydrogen. In fact, 
in the cases of the alkali metals and magnesium the latter action pre- 
ponderated. 
In the above series of experiments it was observed that there was 
no apparent reaction between the excess of chloric acid and the small 
amount of hydrochloric acid formed by reduction. Only a trace of free 
chlorine was observed in one or two cases. Later experiments in con- 
nection with the work on bromic acid showed that the action of chloric 
acid in concentrated solution, on hydrochloric acid of tar greater con- 
centration than could have been obtained by the reduction of chloric 
acid in the experiments cited, was very small. Though these experiments 
have not yet been carried as far as designed, a few results may be stated, 
for their own interest and to make clear the striking difference between 
the results obtained in the study of the action of chloric acid and of 
bromic acid on metals. 
Hydrochloric acid and chloric acid were mixed so as to give them in 
the mixture the respective concentrations, twice normal and four-tenths 
normal, or as 5 to 1, which is the ratio in which they preponderatingly 
react upon each other. The mixture was placed in a glass-stoppered dis- 
tilling flask whose side arm was connected with a ten-bulb column con- 
taining potassium iodide. The flasks w'ere fllled with carbon dioxide 
and placed in the dark closet where the temperature was practically con- 
stant at 20 At the end of deflnite periods the chlorine set free was 
aspirated over into the potassium iodide solution until all color disap- 
peared from the first flask and the liberated iodine was titrated in the 
usual way. The amount of chlorine set tree at the end of 2 hours was 
.0148 gram; at the end of 8 hours, .0256, and at the end of 17 hours, 
.0302 grams. These and other experiments showed that practical equi- 
librium was attained after a few hours, if allowance be made tor the 
chlorine removed by diffusion into the second flask and absorption in 
the potassium iodide solution. 
^Proceedings, 1904, p. 150. 
( 179 ) 
