When copper disks rotate in sulfuric acid solutions, the observed rate of dissolution is first order with respect to the concentration of dichromate ion used as a depolarizer. By studying the effect of temperature and stirring speed at high and low acid concentrations, the process is shown to be determined completely by the rate of transport of dichromate ion to the reacting surface. This has been confirmed by studying the effect of different surface preparations, by measuring the rate of reaction of brass and amalgamated copper with these solutions, and by comparing the observed values with the theoretical rates. The effect of blocking off progressively larger areas of the working surface is reported.
APPENDIX Section 1.--A recent paper by Bayer (2) described the formation of double oxides of the II/V type having a spinel structure. One of the spinel oxides reported was ZnTSb2012(Zn2.33Sb0.6704), formed by reacting 7 moles of ZnO and 1 mole of 8b205 at high temperatures. This work was reproduced prior to this study by re-FORMATION OF Section 2.--The following is a list of the major impurities in the raw materials used in this investigation: NbfOs-Ta, 0.08% (by weight); Si, 0.053%; Ti, 0.0008%; Fe, 0.004%.ZnO-chloride (C1), 0.0008%; sulfur (SO4), 0.003%; Pb, 0.002%; Mn, 0.0000%; substances not pptd by ammonium sulfate, 0.04%.
ABSTRACTIt is suggested that because of concentration polarization only strong acids or strong bases are suitable as electrolytes for commercially acceptable lowtemperature fuel cells. If carbonaceous fuels are employed, acid electrolytes must be used, since alkaline electrolytes would react with the carbon dioxide produced. Experimental results are quoted to show that high performance oxygen and hydrogen electrodes can be made which operate satisfactorily in acid electrolytes. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 138.251.14.35 Downloaded on 2015-03-13 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 138.251.14.35 Downloaded on 2015-03-13 to IP
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