In this paper authors have derived the equations of the polarographic current-voltage curve from the standpoint of chemical kinetics, assuming that the net electrode process is activation-controlled. The results obtained are summarized as follows: (1) Half-wave potential is the constant of the substance concerned, and is independent of its activity. (2) The potential where the current is equal to zero is only defined by the activities of the oxidant and the reductant in the body of the solution. (3) The inflection point of the cathodic or anodic wave agrees with its half-wave potential. (4) The relation between log(I⁄Id–I) and V of the cathodic or anodic wave is a straight line. The values of ΔF1, ΔF2 and a possible to be caluclated from the experimental date. (6) The theoretical curve is essentially the same as the experimental curve of the irreversible type.
(1) It was found that a number of cyanine- and styryl-dyes has a strong inhibitory action upon cholinesterase. (2) Both the specific and non-specific cholinesterase are inhibited by the subtances, the latter being probably more susceptible than the former. (3) The substances have no appreciable effects upon the liver esterase. With the esterase in horse serum, even a slight acceleration of the activity was observed under the influence of some dyes investigated. (4) For some related members of styryl-dyes, a certain relationship between chemical constitution and their inhibitory effects upon cholinesterase could be found.
Activation energies of anodic oxygen-producing reaction on electrode of platinum, magnetite, or natural graphite were measured in aqueous solution of N/10 NaOH under stirring by the stream of oxygen gas, at temperature from about 25° to 65°C. On platinum anode, overvoltage was measured by two methods, (i) by the ordinary method just after 30 minutes from the time of closing the electric circuit, and (ii) by the oscillographic method. The activation energy calculated herefrom was found 15.9 ±2.0 kcals. by (i) method, and 13.8 ±0.6 kcals. by (ii) method. On magnetite and natural graphite, overvoltage was measured by (iii) ordinary method at the stationary state which was obtained after a few minutes. Activation energy of the former was found to be 26.2 ±3.2 kcals., and that of the latter is not obtained. The activation energy on platinum by oscillographic method is consistent with that measured by F. P. Bowden in the aqueous solution of N/5 H2SO4, which is 13–14 kcals. after being corrected about the temperature coefficient of oxygen equilibrium potential. These facts suggest that the anodic oxygenproducing reaction on platinum proceeds through the same ratedetermining step both in acid and alkaline solutions, and the mechanism is rather different on platinum from the one on magnetite.