Homogeneous Catalytic Activation of Molecular Hydrogen in Aqueous Solution by Silver Salts. III Precipitation of Metallic Silver from Solutions of Various Silver Salts

1957 ◽  
Vol 61 (9) ◽  
pp. 1245-1248 ◽  
Author(s):  
A. H. Webster ◽  
J. Halpern
Keyword(s):  
Aqueous Solution ◽  
Molecular Hydrogen ◽  
Metallic Silver ◽  
Catalytic Activation ◽  
Silver Salts

CATALYTIC ACTIVATION OF HYDROGEN IN AQUEOUS SOLUTION BY THE CHLOROPALLADATE(II) ION

1959 ◽  
Vol 37 (9) ◽  
pp. 1446-1450 ◽  
Author(s):  
J. Halpern ◽  
J. F. Harrod ◽  
P. E. Potter
Keyword(s):  
Aqueous Solution ◽  
Ferric Chloride ◽  
Molecular Hydrogen ◽  
Homogeneous Catalyst ◽  
Rate Law ◽  
Catalytic Activation ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

The kinetics of the reduction of ferric chloride by molecular hydrogen in aqueous solution, in the presence of chloropalladate(II), were examined. The latter acts as a homogeneous catalyst for the reaction. The rate-law was found to be,[Formula: see text]where[Formula: see text]The mechanism of the reaction is discussed.

EFFECTS OF COMPLEXING ON THE HOMOGENEOUS REDUCTION OF MERCURIC SALTS IN AQUEOUS SOLUTION BY MOLECULAR HYDROGEN

1956 ◽  
Vol 34 (10) ◽  
pp. 1372-1381 ◽  
Author(s):  
G. J. Korinek ◽  
J. Halpern
Keyword(s):  
Aqueous Solution ◽  
Molecular Hydrogen ◽  
Hydrogen Molecule ◽  
Bimolecular Reaction ◽  
Mercury Atom ◽  
Complexing Agents ◽  
Mercuric Ion ◽  
Rate Determining Step ◽  
Homogeneous Reduction

The effects of various complexing agents on the homogeneous reduction of mercuric salts by molecular hydrogen in aqueous solution were determined. In all cases the kinetics suggest that the rate-determining step is a bimolecular reaction between a mercuric ion or complex and a hydrogen molecule, probably leading to the formation of an intermediate mercury atom. The reactivity of various mercuric complexes was found to decrease in the following order: HgSO4 > Hg++ > HgAc2, HgPr2 > HgCl2 > HgBr2 > Hg(EDA)2++. Addition of anions such as OH−, CO3=, Ac−, Pr−, and Cl−, in excess of the amounts required to form stable mercuric complexes, was found to increase the rate. An interpretation of these effects is given.

scholarly journals Photo-conductance phenomena in the silver halides, and the latent photographic image.―Introduction and Part I

1930 ◽  
Vol 127 (806) ◽  
pp. 613-628 ◽  
Keyword(s):  
Silver Halide ◽  
Metallic Silver ◽  
Direct Part ◽  
Silver Halides ◽  
Photographic Image ◽  
Silver Salts ◽  
Absorption Of Light ◽  
Photographic Emulsions

In studying the mechanism of the photographic process the question naturally arises as to the part played by the silver halides, which form the basis of practically all photographic emulsions. It becomes important to determine whether, or not, the photographic mechanism can be linked up with one or more particular characteristics of these silver salts. Especially is this so in view of the fact that some investigators have developed theories in which the silver halides play no direct part in the photo-reaction taking place on exposure. They have assumed that the absorption of the active light and the resulting process occurs in other light sensitive substances associated with the silver halides in the emulsions, and that the function of the silver halide is merely to act as a source from which metallic silver is produced by the process of development. Weigert especially supports this idea at the present time. It seems to us, however, that the evidence which now exists is not only strongly against this view, but is in favour of the idea that the primary photographic process is intimately concerned with the absorption of light by the silver halides themselves, and may indeed be identified with certain of their characteristic properties.

Sign in / Sign up

Export Citation Format

Share Document