No. 13. [From Proc. Roy. Soc. Edin. 1881, Vol. xi. p. 191.] 



ON THE OXIDATION OF FERROUS SALTS * 



IN this paper the action of permanganate of potassium 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 chemi-t. 



The following solutions were used: 



Ferrous Sulphate. Ordinary recrystallised green vitriol was 

 used. 



( a ) 5*857 grammes FeSO 4 + 7H 2 O dissolved in water and 

 diluted till the solution weighed 290 grammes. This solution 

 contains 0-0407 gramme iron in 10 c.c. 



(b) 4-4600 grammes FeSO 4 + 7H 2 O (= 0-8977 gramme 

 iron) were dissolved in water and made up to 145-5 gram n us. 

 The solution therefore contains 0-062 gramme iron in 10 c.c. 



(c) 25*222 grammes FeSO 4 + 7H 2 O 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. ><>lutioii 

 weighed 514 grammes, therefore the specific gravity <>t tin 

 -"lutinn i- i-ojs ;,t 15 C. This solution when fresh ront.mi- 

 o-i gramme iron in 10 c.c. It was used for most of the obser\ a- 



,<1 extending over nine days, during which time it 

 iuallv deposited a little ochreous matter. Compared with 

 permanganate 10 c.c. rejuir-<l 



M.nvii ii, 17*85 c.c. permanganate. 



M.ir- li [9, i;-' 



Hence the alteration had not been very great, < on^id. -iinu that 

 during these nine days th- -duti<.ii had been consunu-d in 



M- of 10 c.c. at .1 timr 



Chlorate <>f m. 3-654 grammes ren\ -t.tlh-.-d i-hlnrate 



tas>iuin -solved in water and made up to i litre. 



1 Sec Contents, p. xx.>^ 



