402 Gooch and Scoville—Reduction of Selenic Acid 
expected when the mixture, containing one-third of its volume 
of the strongest aqueous hydrochloric acid at the beginning, is 
boiled until all chlorine is expelled, care being taken that the 
volume of the liquid shall not become less than two-thirds of 
the original volume. : 
These are conditions which are easily kept; and we have 
found that from solutions having a total volume of 75 em® and 
containing 25 cm* of the strongest aqueous hydrochloric acid 
(sp. gr. 1°20), the entire amount of chlorine corresponding to 
the reduction of 0°2 grm. of selenic acid to selenious acid is 
liberated in ten minutes. The details of these experiments 
are given in the accompanying table. 
Se == (971 0- = lop 
HCl, Time 
SeO; taken. Total volume sp. gr. 1°20, in SeO; found. 
grm. at the outset. present. minutes. erm. Error. 
0:0572 75 cm* 25 cm® 10 0°0568: 0:0004— 
0°0572 o i Ff 0'0569 0°0003 — 
0'1144 Pa ue ‘ .0°1148 9°0001 — 
0°1144 us « f 0°1137 0°c007 — 
0:1 144 Ke es ee 0°1147 0°0003 + 
0°2288 : x $6 0°2233 0°0005 — 
0°2288 a6 ¥ oe 0°2279 0°0009 — 
Art. XLIV.—The Reduction of Selenic Acid by Potassium 
Bromide in Acid Solution; by F. A. GoocH and W. S. 
SCOVILLE. 
[Contributions from the Kent Chemical Laboratory of Yale College—XLVI.] 
Ir has been shown in previous papers from this laboratory 
that potassium bromide may be used with good effect in pres- 
ence of acid and under well-defined conditions as a reducer of 
arsenic and telluric acids. This paper gives the results of sim- 
ilar experiments made to test the interaction between the 
bromide and selenie acid. . 
In our experiments we have used selenic acid carefully pre- 
pared by oxidizing pure, white, re-sublimed selenium dioxide 
by means of potassium permanganate in the manner described 
in the preceding paper. When intermixed with sulphuric 
acid and potassium bromide, selenic acid liberates bromine 
in proportion to the excess of acid, the bromide, and the 
elevation of the temperature. When such a solution is boiled 
the bromine is evolved and may be collected in potassium 
iodide contained in any appropriate receiver, and the iodine 
