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An electronic device is described for the automatic reversal of the current flowing through an electrochemical cell at a predetermined potential. Provision is made for accurate selection and reproducibility of the potential for current reversal with the accuracy of ± 5 mV. In employing fast mercury-wetted contact relays the device has a switching time of 5 msec.

The chronopotentiometric technique has been used in studying the reduction of uranyl on mercury electrodes in sodium carbonate solutions At 1 M of free carbonate no kinetic complications were observed at experimental conditions pertinent to galvanostatic techniques at quiescent solutions. At low free carbonate concentrations (0.10 M ) the electrochemical reduction is followed by a second order chemical reaction the rate of which is dependent on the concentration of the free carbonate ion. The potential-time relation, is a suitable means of studying the kinetics as dependent on the free ligand concentration and on the concentration of the electroactive uranyl ion. The data indicate that the uranyl tricarbonate complex undergoes reduction without dissociation, while the coupled chemical reaction (disproportionation) involves rearrangement in the transition of uranium(V) into the uranium(IV) and uranium(VI) carbonate complex forms.