of Edinburgh, Session 1880-81. 
191 
6. On the Oxidation of Ferrous Salts. 
By Mr J. Y. Buchanan. 
In this paper the action of permanganate of potash on ferrous 
salts in hydrochloric acid is studied, and a satisfactory method of 
titrating such solutions is indicated. Further, a short study is 
made of the action of chlorates, perchlorates, and nitrates on acid 
ferrous salts under various conditions. The results have a certain 
interest for the analytical chemist. 
The following solutions were used : — • 
Ferrous Sulphate . — Ordinary recrystallised green vitriol was used. 
(a) 5 *857 grammes FeS0 4 + 7H 2 0 dissolved in water and diluted 
till the solution weighed 290 grammes. This solution contains 
0*0407 grammes iron in 10 c.c. 
(h) 4*4600 grammes FeS0 4 + 7H 2 0 ( = 0*8977 grammes iron) 
were dissolved in water and made up to 145*5 grammes. The 
solution therefore contains 0*062 grammes iron in 10 c.c. 
( c ) 25*222 grammes FeS0 4 + 7H 2 0 were dissolved in water and 
made up to 508 c.c. When filled up to the mark, and before adding 
the extra 5 c.c. water, the 500 c.c. solution weighed 514 grammes, 
therefore the specific gravity of the solution is 1*028 at 15° C. 
This solution when fresh contains 0*1 gramme iron in 10 c.c. It 
was used for most of the observations, and extending over nine 
days, during which time it gradually deposited a little ochreous 
matter. Compared with permanganate 10 c.c. required 
March 11, 17*85 c.c. permanganate. 
March 19, 17*6 „ 
Hence the alteration had not been very great, considering that dur- 
ing these nine days the solution had been consumed in portions of 
10 c.c. at a time. 
Chlorate of Potash. — 3*654 grammes recrystallised chlorate of 
potash were dissolved in water and made up to 1 litre. 10 c.c. 
of this solution oxidise 0*1 gramme iron from ferrous to ferric 
salt. 
Perchlorate of Potash . — The perchlorate was obtained from the 
2 B 
VOL. XI. 
