Langenhan—The Arsenical Solutions. 
171 
liquid resulting from the decomposition of the last lot was assayed. 
The following results were obtained:— 
105 gm. 96.09 p. c. KHC 0 3 1,73 p. c. As s 0 3 
65 gm. 94.09 p. c. KHC O 3 1.24 p. c. As s O 3 
. 96.09 p. c. KHCO3 0.07 p. c. As 2 0 3 
j 2.00 p. c. KHCO3 12.3 p. c. As 2 0 3 
. I 15.2 p. c. K s C0 3 
After the removal of the crystals at —10° C. the mother liquor 
was again placed out doors. Twenty-four hours later a second lot 
of crystals was removed, the temperature of the liquid being the 
same. These like the former decomposed at room temperature. 
The assay results are as follows:— 
—10°C Crystals 97.09 p. c. KHC0 3 1.62 p. c. As 2 0 3 
IV.) One gram of arsenic trioxide may be expected to react with 
1.01, 2.02 and 3.04 grams respectively of potassium acid carbonate 
to form arsenites. The ratio of arsenic trioxide to potassium 
bicarbonate in the experiments I,, II, and III, was 1 to 2. Accord¬ 
ing to this there would be an excess of bicarbonate in the first com¬ 
bination, and this excess might be represented by the crystals that 
had been obtained. Hence the equivalent amount of pure 92 potas¬ 
sium carbonate was substituted for the bicarbonate and the experi¬ 
ment repeated on the quarter kilo basis. The solution was allowed 
to stand over night, the crystals removed and assayed in the usual 
manner. 
The following results 
were obtained:— 
Crystals 
35.0 gm. 
96.09 p. c. KHC 0 3 
1.5 p. c. As 2 0 3 
Liquid 
430.6 gm. 
28.00 p. c. K 2 C0 3 
22.5 p, c. As 2 0 3 
Total 
465.00 gm. 
The mother liqour after standing in an open beaker for several 
days deposited a second lot of crystals 93 which assayed:— 
Crystals 10 gm. 89.1 p. c. KHC 0 3 2.9 p. c. As 2 0 3 
92 Pure potassium bicarbonate was heated over a Bunsen flame to a constant 
weight. The resulting residue assayed 99.8 p. c. K 2 C0 3 . 
93 In this lot the crystals were much larger and more of a cubical form. 
When powdered before assaying, a very moist powder resulted. 
30° crystals 
20° crystals 
—10° crystals 
liquid 
