Grove cell

If the polarity of the current is not allowed to change too rapidly, it is possible, since oxidation and reduction occur successively at each pole, to accomplish electrolyses with alternating currents. Experiments with this end in view have been made b Drechsel.1 Dehydration is a case of simultaneous reduction and oxidation. The supposition that in living organisms carbamide is produced from ammonium carbamate by the splitting off of water prompted Drechsel to make experiments in this direction. When an aqueous solution of ammonium carbamate is electrolyzed with a current from a battery of 4-6 Grove cells, and platinum electrodes used, carbamide is obtained independently of the electrode material when alternating currents are employed. The reactions are supposed to be either... 

Bunsen cell - Bunsen replaced the platinum electrode in the -> Grove cell by a - carbon electrode [i]. The Bunsen battery contained a zinc electrode in sulfuric acid and a carbon electrode in nitric acid. The two electrode compartments were separated by a ceramic pot. Bunsen discovered a way to carbonize a mixture of powdered coke and hard coal by strong heating thus foreshadowing the later used graphitizing process [ii, iii]. 

If ft solution of. strychnine be evapomted on a bit of platinum foil, the residue moistened with concentrated H,SO, the foil connected with the 4- pole of a single Grove cell, and a platinum wire from the — pole brought in contact with the surface of the acid, a violet color appears upon the sui-faco of the foil. 

The use of carbon materials in electrochemical systems started in 19 century, when carbon electrodes replaced copper ones in Volta batteries and Pt electrodes in Grove Cells. Nowadays, carbon materials are used in many electrochemical applications because of their high electrical and thermal conductivity, low density, high corrosion resistance, low elasticity adequate strength and high purity. In addition, carbon materials are available in a variety of physical structures (powders, fibres, cloths), have a low cost and can be fabricated into composite structures. 

Platinum in the Grove cell had been replaced by gas carbon by J. T. Cooper in London. Bunsen used carbon prepared by heating a powdered mixture of coal and coke he tried potassium chlorate or dichromate as a depolariser, but found concentrated nitric acid best. At first he used a carbon cylinder soaked in concentrated nitric acid and put into dilute sulphuric acid containing amalgamated zinc, but he soon used a porous clay pot containing a zinc cylinder in dilute sulphuric acid, outside of which was a carbon cylinder in concentrated nitric acid. In later forms, the nitric acid and a carbon plate were inside the porous pot and a zinc cylinder and dilute sulphuric acid outside it. Batteries of Bunsen cells were used to operate arc lanterns, and since they emitted copious fumes of nitrogen dioxide they were usually put out of doors. 

The Grove cell, the first constant element of high electromotive force (i 8 to 2 volts), consisted of zinc in dilute sulphuric acid and platinum in concentrated nitric acid, the liquids being separated by a porous pot. 

Helmholtz thus gives the result with some reservation. He then discusses cells like the Grove cell. The equation A = a -acis identical with Joule s assumption that the virtual intensity is proportional to the chemical heat . 

In the electrolysis of acidulated water, some heat was always evolved with hydrochloric and hydrobromic acids, heat was absorbed (as in the Grove cell). The results indicated that in a solution of several salts in a sufficient quantity of water, a metallic or non-metallic molecule does not seem to behave as if it belonged to any other special molecule, which corresponds with Gay-Lussac s principle of equipollence (1839, see p. 579). 

A wet cell battery has a liquid electrolyte. It is also called as flooded cell, since the liquid covers all internal parts. Wet cells were a precursor to dry cells and are commonly used as a tool for electrochemistry. A particular type of wet cell known as a concentration cell is important in imderstanding corrosion. Wet cells may be primary or secondary cells. Some other primary wet cells are the Leclanche cell. Grove cell, Bunsen cell, chromic acid cell, etc. Wet cells are used in automobile batteries and telecommunication. 

Nitric acid battery (Sir William Robert Grove) The Grove cell delivered twice the voltage of its more expensive rival, the Daniell cell. 

There are monographs concerning fuel cells (141-144). The principle of fuel cells was observed already in 1838 (145). Soon afterwards the Grove cell was developed (146). The Grove cell consisted of a zinc anode in dilute sulfuric acid and a platinum cathode in concentrated nitric acid. The two electrodes were separated by a porous ceramic pot (147). Further aspects of the history of fuel cells have been detailed (148). 

Wikipedia, Grove cell—wikipedia, the free encyclopedia, 2016. [Online accessed ll-July-2016]. 

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