Chemistry. — “Catalysis” VIII. By Nu. Ratan Duar (with A. K. 
Datta and D. N. BHATTACHARYA). (Communicated by Prof. 
Ernst COHEN). 
(Communicated at the meeting of September 25, 1920). 
a. Reaction between silver nitrate and ferrous-ammonium sulphate. 
I tried to determine the kinetics of the reaction between ferrous 
ammonium sulphate and silver nitrate. The reaction seems to be 
very rapid. 
When */,, silver nitrate and N/,, ferrous ammonium sulphate are 
mixed at 25°, a bimolecular velocity coefficient of 0.0007 is obtained, 
but unfortunately this coefficient falls off as the chemical reaction 
proceeds. Since the metallic silver formed reacts on the ferric salt 
produced and we get an equilibrium of this nature 
2 Ag + Fe, (SO), = Ag,SO, + 2 FeSO, 
Ag + Fe (NO), = AgNO, + Fe (NO), 
Fet+) (Agt 
ik | eae: aoe at equilibrium = 0:128 
(ef. Noyks en Braun, Jour. Amer. Chem. Soc. 1912, 34, 1016) the 
reaction between ferrous ammonium sulphate and silver nitrate is 
rapid even at 0° and has a small value for its temperature coefficient. 
The reaction is markedly accelerated by acids; nitric, sulphuric, 
citric, tartaric, and acetic acids have been tried; the greater the 
concentration of hydrogen ions, the greater is the velocity. This 
catalytic activity may be utilised in determining the concentration 
of hydrogen ions. 
Magnetic force has practically no effect on this reaction. It is 
extremely sensitive to the influence of dirt ete. 
Potassium nitrate appreciably retards the reaction, so do manganese 
salts very markedly. 
Carbonic acid markedly accelerates the reaction. Boric acid is 
practically witbout any influence. So is phenol, which is probably 
slightly retarding in its effect. Glucose markedly accelerates the 
reaction. This is a case of induced reaction. A mixture of excess of 
silver nitrate and very little of ferrous ammonium sulphate was 
prepared and divided into equal parts, to one of which glucose was 
20 
Proceedings Royal Acad. Amsterdam. Vol XXIII. . 
