Palit, Santi R

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t o  i k e  ^ d i i o tThe Board of Editors does not hold itself responsible for opinions expressed in the letter published in this seot’on. The notes containi )g short reports of original investigations oommu* nioated to this section should not contain many figures and should not exceed 500 words in length* The contributions reaching the Secretary by the 15th of any month may be expected to appear in the issue for the next month. No proof will be sent to the author*30e l e c t r o d e  glow  d u r in g  e l e c t r o l y sis  a n dLIBERATION OF HYDROGEN AND OXYGEN TOGETHER ON THE ELECTRODESSANTI R. PALITDbpabtmbot Oi’ P hysical Chemistiiy,I ndian' Assooiation bob tub Cultivation of Siik n u e ,J adavpuk, Calcutta-32, I ndia .(Received December, 1967)In  a preliminary note (Palit, 1907) the author has reported that on applying a D.C. voltage of about 200 volts, one of the electrodes usually the cathode starts glowing after an initial incubation period. This is accompanied by a sharp drop in current strength, and by the discharge of big bubbles in place of the usual stream of fine bubbles of gas on the glowing electrode as also to some extent’on the other electrode. However, the gas liberated on the electrodes on analysis showed results which are novel, unexpected and hitherto unknown, and the present note makes a preliminary report of the same.Analysis of the Gas— T^he gas liberated on the cathode on analysis was found to contain both hydrogen and oxygen. However, the oxygen content was not constant. Sometimes the gas cllected over the cathode could bo exploded leaving a small residue and at other times the gas could not be exploded by electric spark. The gas collected over various electrolytes (0.2N solutions of hydrochloric acid, ammonium sulphate, barium chloride and potassium chloride) was found to contain on analysis in a Hempel pipette a considerable quantity of oxygen (16 to 50 percent by volume). This is probably the first time that oxygen is reported to be liberated in considerable quantiy at the cathode side. We also cheeked up the composition of the gas liberated on the nomglowing anode. It was observed that as long as the glow does not start on the cathode, the anodic gas is composed of oxygen only. However, when the cathode starts glowing the gas liberated on960h an^e is a mixture of oxygen with a large percentage of hydrogen. Similar thi^s (i.e the presence of oxygen in the cathodic gas and hydrogen in the anodic gas) are observed even under incipient glow condition, i.e. when there is no glow but big bubbles start forming on the respective electrode in place of the usual fine bubles.Faraday s Law We checked up to see the relationship between the extent of eleotrodeoomposition and Faraday’s law. A number of clecirolytes were exa­mined and the results were quite surprising. The volume and composition of the gas liberated by electrodecomposition with the same quantity of (electricity was found to be highly variable with the iiature of the electrolyte and was usually in exoess of tha t given by Faraday’s law^ Hewever, the n^producibility was poor, there being large variation in yield freSrn experiment to experiment under a])pa- rently the same conditions. Evidently, Faraday’s law has nothing to do with this reported phenomenon and the mechanism must be different from normal ionic conduction mechanism.Mechanism—It is difficult from such preliminary information to venture a about the mechanism of the observation in question. Tt was first thought that along with usual electrolysis another concurrent decomposition of water was taking place cither due to the catalytic decomposit ion of water vapour on the glowing electrode, or due to localised high potential gradient owing to micro- cavity formation, or duo to some local action. This idea agreed quite well with observations on barium chloride solution whicli givt s this glow very well and wht're the volume of oxygen liberated at tlie catlioch? sidi  ^ is below 20 per cent. How­ever, in some other cases (HCI, NaOH and KCl) this idea is untenable as the oxygen content of the cathodic gas is between 40 to 50 per cent. Plain decom­position of Water can not account for more than one-third volume of oxygen. Besides, the idea of catalytic thermal decomposition of water can not be support­ed on thermodynamic grounds. The sudden drop of current along with disappear­ance of turbulence a t the onset or ncar-onset of glow is very significant and is analogous to somedischarge and glow phenomena in gases. Probably some kind of explanation from that field has to be invoked. However, it appears th a t some ion radicals (probably charged molecular aggregates of water) are involved. This is inferred from the fact that the intensity of glow as well as current strength decreases on applying a magnetic field at right angles to the flow of current. Further experiments are in progress and detailed results willbe published later.Thanks are due to Prithwis Kumar Basu for experimental assistance.r e f e r e n c ePalit, S. R., 1967, Indim J, Vhys, 41 809.Leit&ts to the Editor g01

Electrode Glow During Electrolysis and Liberation of Hydrogen and Oxygen Together on the Electrodes

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Electrode Glow During Electrolysis and Liberation of Hydrogen and Oxygen Together on the Electrodes

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