The potential of saturated α-palladium in hydrogen-stirred solution compared to a Pt/H2 electrode in the same solution is 0.0495±0.0005 v. The potential-determining reaction on α-palladium is independent of hydrogen pressure. The potential-determining equilibrium is postulated to be, H++e= lim Pd(Pd−H)α. Pure palladium spontaneously absorbs hydrogen in hydrogen-stirred solution until the saturation limit of the α phase is reached. This limiting atomic ratio of H/Pd=0.025±0.005. Between a H/Pd atomic ratio of 0.03 to 0.36 both the α and β phases coexist and the mixed potential is determined by that of the α domains. In the H/Pd region 0.36 to 0.6, the potential is a function of the hydrogen content of the palladium.

A simple formalism is developed in which the determinantal equation for the reciprocal relaxation times of a reaction mechanism can be written down immediately from an inspection of the elementary chemical reactions in the mechanism. The reactions in the mechanism may be of any order; parallel reaction paths may be included. The determinantal equation can be solved for the relaxation times using the simple formalism and the expressions in terms of rate constants and equilibrium concentrations obtained at the end of the procedure. If the reactions are not thermodynamically independent then the order of the determinantal equation can be reduced directly in a simple way to that corresponding to the number of thermodynamically independent reactions. The procedure and the various approximational techniques are illustrated by a number of detailed examples. A number of general results are derived. It is pointed out that for kinetically elementary reactions, the matrix of Onsager coefficients is diagonal. The diagonal element is proportional to the exchange rate of the elementary reaction. It is shown that the transformation to normal coordinates can be done by using a product of a diagonal matrix and an orthogonal matrix. This simplifies the inversion of the transformation considerably. For systems with thermodynamically dependent reactions the explicit form of the time independent coordinates is derived. Some general relations between the elements of the transformation matrix are also derived.

Heat of Solution of Hydrogen in a Two-phase Pd-H Alloy 1123 in the introduction depended on the observed first power dependence of the uranium extraction coefficients, [U]

In recent years the application of relaxation techniques to the study of fast reactions has received considerable attention. Eigen and deMaeyer2 have developed the theory and experimental techniques for studying such reactions. However, little attention has been Contribution from Monsanto Chemical Company,

It is shown that the current density‐overpotential relationship for several mechanisms of the hydrogen evolution reaction can be expressed conveniently in terms of one or the other of two characteristic functions: g1=}{exp][)( α−12 η normalsinh )( 12η  /i,g2= tanh 12η /i½. The following parameters are convenient: a, the transfer coefficient for the oxidation reaction; θ0 , the fraction of the surface covered by H atoms at equilibrium, io=false(normaldi/dη)η=0 ; and ρ=false{d normalIn false[θ/false(1−θfalse)false]/dη}η=o . In the important special cases, the appropriate characteristic function is a simple function of the overpotential over the entire range of anodic and cathodic values. The evaluation of the parameters involved is discussed.

Strips of copper foil were plated with a thin deposit of radioactive copper and the specimens then oxidized in air at 800°, 900°, 1000°C. From the distribution of radioactive copper in the oxide diffusion coefficients, D, for cuprous ion in cuprous oxide were calculated. Over the temperature range D was found to be 0.0358 exp(−37,000/RT) cm2 sec.−1. The activation energy for the oxidation of copper is 39±2 kcal./mole, so that these measurements provide further evidence that diffusion of Cu+ in Cu2O is the rate-determining step in the oxidation.

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It is the purpose of this article to present several graphic examples of key relationships in the subject of phase equilibria.