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electrolysis

electrolysis

electrolysis Sentence Examples

  • Electrolysis of a solution in hydrofluoric acid gives cobaltic fluoride, CoF3.

  • This acid may also be prepared by the electrolysis of concentrated sulphuric acid, and it is distinguishable from persulphuric acid by the fact that it immediately liberates iodine from potassium iodide.

  • From the behaviour of substances on electrolysis he assumed that all substances had two components, one bearing a negative charge, the other a positive charge.

  • Berzelius's investigation of the action of the electric current on salts clearly demonstrated the invaluable assistance that electrolysis could render to the isolator of elements; and the adoption of this method by Sir Humphry Davy for the analysis of the hydrates of the metals of the alkalis and alkaline earths, and the results which he thus achieved, established its potency.

  • Matthiessen in 1855, who obtained the metal by electrolysis and thoroughly examined it and its compounds.

  • Balard completed for many years Berzelius's group of " halogen " elements; the remaining member, fluorine, notwithstanding many attempts, remained unisolated until 1886, when Henri Moissan obtained it by the electrolysis of potassium fluoride dissolved in hydrofluoric acid.

  • By his own investigations and those of Sir Edward Frankland it was proved that the radical methyl existed in acetic acid; and by the electrolysis of sodium acetate, Kolbe concluded that he had isolated this radical; in this, however, he was wrong, for he really obtained ethane, C 2 H 6, and not methyl, CH 3.

  • Since then the subject has been extensively studied, more particularly by Alexander Classen, who has summarized the methods and results in his Quantitative Chemical Analysis by Electrolysis (1903).

  • The electrolysis is generally conducted with platinum electrodes, of which the cathode takes the form of a piece of foil bent into a cylindrical form, the necessary current being generated by one or more Daniell cells.

  • Transformations of electrical into chemical energy are witnessed in the processes of electrolysis (q.v.; see also Electrochemistry and Electrometallurgy).

  • Journ., 1811, 8, p. 302), and obtained by the action of chlorine or sodium hypochlorite on ammonium chloride, or by the electrolysis of ammonium chloride solution, is a very volatile yellow oil.

  • ELECTROLYSIS (formed from Gr.

  • When the passage of an electric current through a substance is accompanied by definite chemical changes which are independent of the heating effects of the current, the process is known as electrolysis, and the substance is called an electrolyte.

  • Faraday examined also the electrolysis of certain fused salts such as lead chloride and silver chloride.

  • Thus the hydroxyl mentioned above decomposes into water and oxygen, and the chlorine produced by the electrolysis of a chloride may attack the metal of the anode.

  • This leads us to examine more closely the part played by water in the electrolysis of aqueous solutions.

  • The obvious phenomena to be explained by any theory of electrolysis are the liberation of the products of chemical decomposition at the two electrodes while the intervening liquid is unaltered.

  • These views were applied to the theory of electrolysis by R.

  • Interchanges must be supposed to go on whether a current passes or not, the function of the electric forces in electrolysis being merely to determine in what direction the parts of the molecules shall work their way through the liquid and to effect actual separation of these parts (or their secondary products) at the electrodes.

  • The verification of Kohlrausch's theory of ionic velocity verifies also the view of electrolysis which regards the electric current as due to streams of ions moving in opposite directions through the liquid and carrying their opposite electric charges with them.

  • Clausius extended to electrolysis the chemical ideas which looked on the opposite parts of the molecule as always changing partners independently of any electric force, and regarded the function of the current as merely directive.

  • Whetham, The Theory of Solution and Electrolysis (Cambridge, 1902); M.

  • In the article Electrolysis it is shown how the passage of an electric current through a solution containing metallic ions involves the deposition of the metal on the cathode.

  • Under these conditions electrolysis of the solution in the brush takes place.

  • Zinc is commonly deposited by electrolysis on iron or steel goods which would ordinarily be "galvanized," but which for any reason may not conveniently be treated by the method of immersion in fused zinc. The zinc cyanide bath may be used for small objects, but for heavy goods the sulphate bath is employed.

  • Electrolysis has in a few instances been applied to processes of manufacture.

  • Among other subjects at which he subsequently worked were the absorption of gases in blood (1837-1845), the expansion of gases by heat (1841-1844), the vapour pressures of water and various solutions (1844-1854), thermo-electricity (1851), electrolysis (1856), induction of currents (1858-1861), conduction of heat in gases (1860), and polarization of heat (1866-1868).

  • Betts, Lead Refining by Electrolysis (1908); M.

  • By electrolysis it yields uranium dioxide as a pyrophoric powder, and peruranic hydroxide, U04.2H20, when treated with hydrogen peroxide.

  • Potassium percarbonate, K 2 C 2 0 6, is obtained in the electrolysis of potassium carbonate at -10 to -15°.

  • Canvas diaphragms were used to prevent the acid formed by electrolysis at the anode from mixing with the cathode liquor, and so hindering deposition.

  • 13,336 of 1894) a rapidly rotating cathode is used in a chloride solution, a porous partition separating the tank into anode and cathode compartments, and the chlorine generated by electrolysis at the anode being recovered.

  • In many of these the application of heat is necessary to bring the substances used into the liquid state for the purpose of electrolysis, aqueous solutions being unsuitable.

  • 30) obtained potassium by the electrolysis of a mixture of potassium and calcium chlorides fused over a lamp. There are here foreshadowed two types of electrolytic furnace-operations: (a) those in which external heating maintains the electrolyte in the fused condition, and (b) those in which a currentdensity is applied sufficiently high to develop the heat necessary to effect this object unaided.

  • But in some cases in which the current is used for electrolysis and for the production of extremely high temperatures, for which the calorific intensity of ordinary fuel is insufficient, the electric furnace is employed with advantage.

  • The reduction is not due to electrolysis, but to the action of carbon on alumina, a part of the carbon in the charge being consumed and evolved as carbon monoxide gas, which burns at the orifice in the cover so long as reduction is taking place.

  • Sainte Claire Deville working independently obtained aluminium by the electrolysis of the fused double sodium aluminium chloride.

  • For the theory and elemental laws of electro-deposition see Electrolysis; and for the construction and use of electric generators see Dynamo and Battery: Electric. The importance of the subject may be gauged by the fact that all the aluminium, magnesium, sodium, potassium, calcium carbide, carborundum and artificial graphite, now placed on the market, is made by electrical processes, and that the use of such processes for the refining of copper and silver, and in the manufacture of phosphorus, potassium chlorate and bleach, already pressing very heavily on the older non-electrical systems, is every year extending.

  • The chlorine reacts with the caustic soda, forming sodium hypochlorite, and this in turn, with an excess of chlorine and at higher temperatures, becomes for the most part converted into chlorate, whilst any simultaneous electrolysis of a hydroxide or water and a chloride (so that hydroxyl and chlorine are simultaneously liberated at the anode) also produces oxygen-chlorine compounds direct.

  • It is obvious that, with suitable methods and apparatus, the electrolysis of alkaline chlorides may be made to yield chlorine, hypochlorites (bleaching liquors), chlorates or caustic alkali, but that great care must be exercised if any of these products is to be obtained pure and with economy.

  • pp. 198, 329, 43 8) in connexion with the electrolysis of hydrochloric acid.

  • Hermite, which consisted in the production of bleach-liquors by the electrolysis (according to the 1st edition of the 1884 patent) of magnesium or calcium chloride between platinum anodes carried in wooden frames, and zinc cathodes.

  • His system for the disinfection of sewage and similar matter by the electrolysis of chlorides, or of sea-water, has been tried, but for the most part abandoned on the score of expense.

  • Again, anode reactions, such as are observed in the electrolysis of the fatty acids, may be utilized, as, for example, when the radical CH3C02 - deposited at the anode in the electrolysis of acetic acid - is dissociated, two of the groups react to give one molecule of ethane, C 2 H 6, and two of carbon dioxide.

  • Use has been made of electrolysis in tanning operations, the current being passed through the tan-liquors containing the hides.

  • The production of ozone in small quantities during electrolysis, and by the so-called silent discharge, has long been known, and the Siemens induction tube has been developed for use industrially.

  • In Berzelius' system + potassium sulphate is to be regarded as K 2 0.S0 3; electrolysis should simply effect the disruption of the positive and negative components, potash passing with the current, and sulphuric acid against the current.

  • Gold is also attacked when strong sulphuric acid is submitted to electrolysis with a gold positive pole.

  • Other metals which find application in the metallurgy of gold by virtue of their property of extracting the gold as an alloy are lead, which combines very readily when molten, and which can afterwards be separated by cupellation, and copper, which is separated from the gold by solution in acids or by electrolysis; molten lead also extracts gold from the copper-gold alloys.

  • electrolysis.

  • The precipitation is effected by zinc in the form of bright turnings, or coated with lead, or by electrolysis.

  • Siemens and Halske, essentially consists in the electrolysis of weak solutions with iron or steel plate anodes, and lead cathodes, the latter, when coated with gold, being fused and cupelled.

  • The metal has been obtained by electrolysis of a mixture of caesium and barium cyanides (C. Setterberg, Ann., 1882, 211, p. loo) and by heating the hydroxide with magnesium or aluminium (N.

  • The dioxide, 0s0 2, is formed when potassium osmichloride is heated with sodium carbonate in a current of carbon dioxide, or by electrolysis of a solution of the tetroxide in the presence of alkali.

  • Amphiaraus, foreseeing the disastrous issue of the war, at first refused to share in it; he had, however, promised Eriphyle when he married her that, in the event of any dispute arising between her brother and ' See " The Electrolysis of Copper Sulphate in Standardizing Electrical Instruments," by A.

  • Davy, inspired by his successful isolation of the metals sodium and potassium by the electrolysis of their hydrates, attempted to decompose a mixture of lime and mercuric oxide by the electric current; an amalgam of calcium was obtained, but the separation of the mercury was so difficult that even Davy himself was not sure as to whether he had obtained pure metallic calcium.

  • Electrolysis of lime or calcium chloride in contact with mercury gave similar results.

  • filr Electrochemie, 1902, p. 8757) obtained the metal of 90% purity by electrolysing calcium chloride at a temperature of about 780°, using an iron cathode, the anode being the graphite vessel in which the electrolysis was carried out.

  • On electrolysis a layer of metallic calcium is formed at the lower end of this rod on the surface of the electrolyte; the rod is gradually raised, the thickness of the layer increases, and ultimately a rod of metallic calcium, forming, as it were, a continuation of the iron cathode, is obtained.

  • The metal as prepared by electrolysis generally contains traces of aluminium and silica.

  • Moissan in 1886 by the electrolysis of pure anhydrous hydrofluoric acid containing dissolved potassium fluoride.

  • Whilst the electrolysis is proceeding, the apparatus is kept at a constant temperature of - 23° C. by means of liquid methyl chloride.

  • During electrolysis, oxygen is evolved at the anode and escapes from the outer vessel, while the sodium deposited in globules on the cathode floats upwards into the iron cylinder, within which it accumulates, and from which it may be removed at intervals by means of a perforated iron ladle, the fused salt, but not the metal, being able to pass freely through the perforations.

  • Meyer, Ber., 1876, 9, P. 543), C3H7NH 2 +HNO 2 =N 2 +2H 2 O+C 3 H 6; by the electrolysis of the alkali salts of saturated dicarboxylic acids; by the decomposition of 0-haloid fatty acids with sodium carbonate, CH 3 CHBr CH(CH 3) CO 2 H =CO 2 -1-HBr+CH 3 CH :CH CH 3; by distilling the barium salts of acids Cn,H 2, ,,- 2 0 2 with sodium methylate in vacuo (I.

  • Moissan found that the oxide resisted reduction by carbon in the electric furnace, so that electrolysis of a fusible salt of the metal must be resorted to.

  • Borchers also used an externally heated metal vessel as the cathode; it is provided with a supporting collar or flange a little below the top, so that the upper part of the vessel is exposed to the cooling influence of the air, in order that a crust of solidified salt may there be formed, and so prevent the creeping of the electrolyte over the top. The carbon anode passes through the cover of a porcelain cylinder, open at the bottom, and provided with a side-tube at the top to remove the chlorine formed during electrolysis.

  • His work included investigations of osmic acid, of the ferrates, stannates, plumbates, &c., and of ozone, attempts to obtain free fluorine by the electrolysis of fused fluorides, and the discovery of anhydrous hydrofluoric acid and of a series of acides sulphazotes, the precise nature of which long remained a matter of discussion.

  • The subject is dealt with in Electrolysis and Electric conduction: § dealt with the relations between the properties of an ideally dilute solution, we now turn to the consideration of the general case where the simplifying assumption of great dilution is not made.

  • The special properties of these solutions are dealt with under Electrolysis and Electric conduction, § In Liquids.

  • Hall, by devising the electrolytic method now in use, inaugurated the present era of industrial electrolysis.

  • If, according to the present method of winning the metal, a bath containing silica as well as alumina is submitted to electrolysis, both oxides are dissociated, and as silicon is a very undesirable impurity, an alumina contaminated with silica is not suited for reduction.

  • Many metals, of which copper, silver and nickel are types, can be readily won or purified by the electrolysis of aqueous solutions, and theoretically it may be feasible to treat aluminium in an identical manner.

  • Of the simple compounds, only the fluoride is amenable to electrolysis in the fused state, since the chloride begins to volatilize below its melting-point, and the latter is only 5° below its boiling-point.

  • This preparation of a chlorine compound suited for electrolysis becomes more costly and more troublesome than that of the oxide, and in addition four times as much raw material must be handled.

  • That this process did not depend upon electrolysis, but was simply an instance of electrical smelting or the decomposition of an oxide by means of carbon at the temperature of the electric arc, is shown by the fact that the Cowles furnace would work with an alternating current.

  • In 1886 he succeeded in obtaining the element fluorine in the free state by the electrolysis of potassium fluoride and anhydrous hydrofluoric acid at a low temperature.

  • It may be prepared by the electrolysis of acidulated water, by the decomposition of water by various metals or metallic hydrides, and by the action of many metals on acids or on bases.

  • Naumann and C. Pistor, Ber., 1885, 18, p. 1647), or by the electrolysis of a dilute solution of caustic soda (C. Winssinger, Chem.

  • Palladium and some other metals are capable of absorbing large volumes of hydrogen (especially when the metal is used as a cathode in a water electrolysis apparatus).

  • Traube, Ber., 1882, 15, p. 659); in the oxidation of zinc, lead and copper in presence of water, and in the electrolysis of sulphuric acid of such strength that it contains two molecules of water to one molecule of sulphuric acid (M.

  • Ann., 1875, 156, p. 466) on electrolysis of the fused chloride, while C. Winkler (Ber., 1890, 23, p. 78) prepared it by heating the oxide with a mixture of magnesium and magnesia.

  • From the filtered solution the thallium is recovered, as such, by means of pure metallic zinc, or by electrolysis.

  • Norton have prepared it by the electrolysis of the melted chloride (Pogg.

  • - Some of the chlorine manufactured (practically only such as is obtained by the electrolysis of chlorides) is con densed by cold and pressure into liquid chlorine.

  • Electrolitic Alkali Manufacture In theory by far the simplest process for making alkalis together with free chlorine is the electrolysis of sodium (or potassium) chloride.

  • Precisely the same can be done in the electrolysis of potassium chloride.

  • The first patents for the electrolysis of alkaline chlorides were taken out in 1851 and several others later on; but commercial success was utterly impossible until the invention of the dynamo machine allowed the production of the electric current at a sufficiently cheap rate.

  • de Montlaur; a few years later the processes worked out at the Griesheim alkali works (near Frankfort) for the manufacture of caustic potash and chlorine established definitely the success of electrolysis in the field of potash, but even then none of the various processes working with sodium chloride had emerged from the experimental stage.

  • Only more recently the manufacture of caustic soda by electrolysis has also been established as a permanent and paying industry, but as the greatest secrecy is maintained in everything belonging to this domain, and as neither patent specifications nor the sanguine assertions and anticipations of interested persons throw much real light on the actual facts of the case, nothing certain can be said either in regard to the date at which the profitable manufacture of caustic soda was first carried out by electrolysis, or as to what extent this is the case at the present moment.

  • The electrolysis is carried on until about a quarter of the chloride has been transformed; it must be stopped at this stage lest the formation of hypochlorite and chlorate should set in.

  • The electrolysis takes place in the central compartment of a tripartite trough which can be made to rock slightly either to one side or the other.

  • As the electrolysis goes on, NaOH is formed at the cathodes and remains at the bottom.

  • The metal is obtained from zinc blende (which only contains it in very small quantity) by dissolving the mineral in an acid, and precipitating the gallium by metallic zinc. The precipitate is dissolved in hydrochloric acid and foreign metals are removed by sulphuretted hydrogen; the residual liquid being then fractionally precipitated by sodium carbonate, which throws out the gallium before the zinc. This precipitate is converted into gallium sulphate and finally into a pure specimen of the oxide, from which the metal is obtained by the electrolysis of an alkaline solution.

  • Peligot), by electrolysis of nickel ammonium sulphate (Winkler, Zeit.

  • Sodium hypochlorite can be prepared by the electrolysis of brine solution in the presence of carbon electrodes, having no diaphragm in the electrolytic cell, and mixing the anode and cathode products by agitating the liquid.

  • It is also produced by the electrolysis of a concentrated solution of potassium ethyl malonate.

  • Succinonitrile, C2H4(CN)2r is obtained by the action of potassium cyanide on ethylene dibromide or by the electrolysis of a solution of potassium cyanacetate.

  • The modern process consists in the electrolysis of a hot solution of potassium chloride, or, preferably, the formation of sodium chlorate by the electrolytic method and its subsequent decomposition by potassium chloride.

  • The phenomena attendant on the passage of electricity through solids, through liquids and through gases, are described in the article Electric conduction, and also Electrolysis, and the propagation of electrical vibrations in Electric Waves.

  • In the 7th series (1834) he defines a number of new terms, such as electrolyte, electrolysis, anode and cathode, &c., in connexion with electrolytic phenomena, which were immediately adopted into the vocabulary of science.

  • His most important contribution at this date was the invention of the voltameter and his enunciation of the laws of electrolysis.

  • Furthermore his electrochemical investigations, and particularly his discovery of the important law of electrolysis, that the movement of a certain quantity of electricity through an electrolyte is always accompanied by the transfer of a certain definite quantity of matter from one electrode to another and the liberation at these electrodes of an equivalent weight of the ions, gave foundation for the idea of a definite atomic charge of electricity.

  • The general facts and laws of electrolysis were determined experimentally by Davy and Faraday and confirmed by the researches of J.

  • The modern theory of electrolysis grew up under the hands of R.

  • For the hydrogen atom the ratio of charge to mass as deduced from electrolysis is about Io 1.

  • But it was not until the dynamo was improved as a machine for generating large quantities of electricity at a very low cost that the electrolysis of copper could be practised on a commercial scale.

  • Such a degree of purity is, however, unattainable unless the conditions of electrolysis are rigidly adhered to.

  • The advantage of keeping the solution in motion is due partly to the renewal of solution thus effected in the neighbourhood of the electrodes, and partly to the neutralization of the tendency of liquids undergoing electrolysis to separate into layers, due to the different specific gravities of the solutions flowing from the opposing electrodes.

  • Henry Wilde, in 1875, in depositing copper on iron printing-rollers, recognized this principle and rotated the rollers during electrolysis, thereby renewing the surfaces of metal and liquid in mutual contact, and imparting sufficient motion to the solution to prevent stratification; as an alternative he imparted motion to the electrolyte by means of propeller blades.

  • Elmore, who sought to improve the character of the deposit by burnishing during electrolysis, of E.

  • Similar phenomena are exhibited in the electrolysis of solutions of antimony tribromide and tri-iodide, the product obtained from the tribromide having a specific gravity of 5.4, and containing 18-20% of antimony tribromide, whilst that from the tri-iodide has a specific gravity of 5.2-5.8 and contains about 22% of hydriodic acid and antimony tri-iodide.

  • 173) obtained the value 121 from the electrolysis of the chloride.

  • The deposit from this solution even with low currentdensities is pulverulent and non-coherent, and therefore during electrolysis wooden scrapers are automatically and intermittently passed over the surface of the cathode to detach the loose silver, which falls into cloth trays at the bottom of the tanks.

  • Silver peroxide, AgO, appears under certain conditions as minute octahedra when a solution of silver nitrate is electrolysed, or as an amorphous crust in the electrolysis of dilute sulphuric acid between silver electrodes.

  • It is also obtained in the electrolysis of solutions of selenious acid (C. Manuelli and G.

  • Meyer (Ber., 1902, 35, p. 1 59 1) by the electrolysis of silver selenite in the presence of potassium cyanide obtained the value 79.22.

  • Gin, L'Electricien, 1903, 2 5, p. 5); and by the electrolysis of vanadium trioxide when heated in an evacuated glass tube (W.

  • Arsenic trihydride (arsine or arseniuretted hydrogen), AsH3, is formed by decomposing zinc arsenide with dilute sulphuric acid; by the action of nascent hydrogen on arsenious compounds, and by the electrolysis of solutions of arsenious and arsenic acids; it is also a product of the action of organic matter on many arsenic compounds.

  • Titanium Titanium metal made by electrolysis of titanium dioxide in molten calcium chloride.

  • To obtain the rare, pure copper requires smelting, leaching, or electrolysis.

  • He died in 1954 from taking potassium cyanide at his home where he was performing electrolysis experiments.

  • equilibrium electrochemistry The above are all examples of electrolysis reactions, where an electron is forced in or out of the electrode.

  • Know that aqueous solutions of ionic compounds will also undergo electrolysis.

  • Gaseous hydrogen can also be made when it is separated from the oxygen atoms in water using electricity via a process called electrolysis.

  • Then use electrolysis to transfer all the copper from the impure anode to the cathode.

  • There is a small risk associated with tattooing, electrolysis, ear piercing and acupuncture.

  • The SkinGenesis hair removal treatment means there is no need for waxing, electrolysis or lasers.

  • Carefully controlled electrolysis migrates metal atoms to the mandrel until the desired thickness is attained.

  • The electrolytic extraction of sodium Sodium, like many reactive metals, can be extracted by electrolysis of its molten chloride.

  • The final project is looking at the dynamic response of the system where hydrogen is being produced by electrolysis powered by a wind turbine.

  • Sodium chloride is a very important raw material from which hydrogen, chlorine and sodium hydroxide can be manufactured by electrolysis.

  • Skin piercing The skin piercing activities which are controlled by registration are Acupuncture Tattooing Ear piercing electrolysis A fee is required.

  • electrolysis reaction also uses a catalyst to increase the energy release in the process.

  • electrolysis process stops.

  • electrolysis cell tank.

  • electrolysis experiments.

  • Four of the nine hydrogen stations in CUTE will supply hydrogen produced through water electrolysis.

  • The condition of the water in the pool is controlled automatically by the latest salt electrolysis system whereby no chemicals are used.

  • electrolysis of water.

  • Topic 8: The electrolysis of salt - page 43 of the revision guide What are the products of the electrolysis of salt - page 43 of the revision guide What are the products of the electrolysis of salt water?

  • electrolysis of aluminum oxide in the manufacture of aluminum.

  • electrolysis of a molten metallic fluoride (perhaps potassium fluoride KF?

  • Fluorine for the manufacturing process was generated on-site by electrolysis of a molten metallic fluoride (perhaps potassium fluoride KF?

  • fluorine for the manufacturing process was generated on-site by electrolysis of a molten metallic fluoride (perhaps potassium fluoride KF?

  • Gilding can be done either professionally by electrolysis or using gold leaf.

  • hydrogen by electrolysis of water.

  • He died in 1954 from taking potassium cyanide at his home where he was performing electrolysis experiments.

  • The topics reviewed are: redox reactions, Hess's Law, balancing ion electron half equations, redox titrations and electrolysis.

  • Consider for example, the electrolysis of the molten salt, NaCl.

  • tattooing, ear piecing or electrolysis, where the skin is pierced.

  • tattooing, ear piercing or electrolysis unless a license has been formally approved.

  • The topics reviewed are: redox reactions, Hess's Law, balancing ion electron half equations, redox titrations and electrolysis.

  • tweezewill never need to deal with waxing, tweezing, laser or electrolysis again.

  • Electrolysis of a solution in hydrofluoric acid gives cobaltic fluoride, CoF3.

  • 59, p. 760) has prepared cobaltic sulphate C02(S04)3.18H20, in the form of small needles, by the electrolysis of cobalt sulphate.

  • If in a vessel of nitric acid are placed a large platinum plate and a platinum electrode of very small surface such as that produced when an extremely fine platinum wire is slightly immersed in the liquid, and if a current from a single voltaic cell is passed through the electrolytic cell so that the fine wire is the anode or positive pole, then the small surface will be polarized or covered with a film of gas due to electrolysis (fig.

  • This acid may also be prepared by the electrolysis of concentrated sulphuric acid, and it is distinguishable from persulphuric acid by the fact that it immediately liberates iodine from potassium iodide.

  • From the behaviour of substances on electrolysis he assumed that all substances had two components, one bearing a negative charge, the other a positive charge.

  • Berzelius's investigation of the action of the electric current on salts clearly demonstrated the invaluable assistance that electrolysis could render to the isolator of elements; and the adoption of this method by Sir Humphry Davy for the analysis of the hydrates of the metals of the alkalis and alkaline earths, and the results which he thus achieved, established its potency.

  • Matthiessen in 1855, who obtained the metal by electrolysis and thoroughly examined it and its compounds.

  • Balard completed for many years Berzelius's group of " halogen " elements; the remaining member, fluorine, notwithstanding many attempts, remained unisolated until 1886, when Henri Moissan obtained it by the electrolysis of potassium fluoride dissolved in hydrofluoric acid.

  • By his own investigations and those of Sir Edward Frankland it was proved that the radical methyl existed in acetic acid; and by the electrolysis of sodium acetate, Kolbe concluded that he had isolated this radical; in this, however, he was wrong, for he really obtained ethane, C 2 H 6, and not methyl, CH 3.

  • Since then the subject has been extensively studied, more particularly by Alexander Classen, who has summarized the methods and results in his Quantitative Chemical Analysis by Electrolysis (1903).

  • The electrolysis is generally conducted with platinum electrodes, of which the cathode takes the form of a piece of foil bent into a cylindrical form, the necessary current being generated by one or more Daniell cells.

  • Transformations of electrical into chemical energy are witnessed in the processes of electrolysis (q.v.; see also Electrochemistry and Electrometallurgy).

  • Arndt, Ber., 1899, 32, p. 2136); by the oxidation of hydroxylamine (ibid., 1900, 33, p. 30); and by the electrolysis of hydrazine and its salts (E.

  • Journ., 1811, 8, p. 302), and obtained by the action of chlorine or sodium hypochlorite on ammonium chloride, or by the electrolysis of ammonium chloride solution, is a very volatile yellow oil.

  • ELECTROLYSIS (formed from Gr.

  • When the passage of an electric current through a substance is accompanied by definite chemical changes which are independent of the heating effects of the current, the process is known as electrolysis, and the substance is called an electrolyte.

  • During the earliest investigation of the subject it was thought that, since hydrogen and oxygen were usually evolved, the electrolysis of solutions of acids and alkalis was to be regarded as a direct decomposition of water.

  • Faraday examined also the electrolysis of certain fused salts such as lead chloride and silver chloride.

  • Thus the hydroxyl mentioned above decomposes into water and oxygen, and the chlorine produced by the electrolysis of a chloride may attack the metal of the anode.

  • This leads us to examine more closely the part played by water in the electrolysis of aqueous solutions.

  • In the electrolysis of a concentrated solution of sodium acetate, hydrogen is evolved at the cathode and a mixture of ethane and carbon dioxide at the anode.

  • The obvious phenomena to be explained by any theory of electrolysis are the liberation of the products of chemical decomposition at the two electrodes while the intervening liquid is unaltered.

  • These views were applied to the theory of electrolysis by R.

  • Interchanges must be supposed to go on whether a current passes or not, the function of the electric forces in electrolysis being merely to determine in what direction the parts of the molecules shall work their way through the liquid and to effect actual separation of these parts (or their secondary products) at the electrodes.

  • The verification of Kohlrausch's theory of ionic velocity verifies also the view of electrolysis which regards the electric current as due to streams of ions moving in opposite directions through the liquid and carrying their opposite electric charges with them.

  • Clausius extended to electrolysis the chemical ideas which looked on the opposite parts of the molecule as always changing partners independently of any electric force, and regarded the function of the current as merely directive.

  • Whetham, The Theory of Solution and Electrolysis (Cambridge, 1902); M.

  • In the article Electrolysis it is shown how the passage of an electric current through a solution containing metallic ions involves the deposition of the metal on the cathode.

  • Under these conditions electrolysis of the solution in the brush takes place.

  • Zinc is commonly deposited by electrolysis on iron or steel goods which would ordinarily be "galvanized," but which for any reason may not conveniently be treated by the method of immersion in fused zinc. The zinc cyanide bath may be used for small objects, but for heavy goods the sulphate bath is employed.

  • Electrolysis has in a few instances been applied to processes of manufacture.

  • Among other subjects at which he subsequently worked were the absorption of gases in blood (1837-1845), the expansion of gases by heat (1841-1844), the vapour pressures of water and various solutions (1844-1854), thermo-electricity (1851), electrolysis (1856), induction of currents (1858-1861), conduction of heat in gases (1860), and polarization of heat (1866-1868).

  • The formation of lead dioxide by the electrolysis of a lead solution, the anode being a lead plate coated with lead oxide or sulphate and the cathode a lead plate, is the fundamental principle of the storage cell (see Accumulator).

  • Betts, Lead Refining by Electrolysis (1908); M.

  • By electrolysis it yields uranium dioxide as a pyrophoric powder, and peruranic hydroxide, U04.2H20, when treated with hydrogen peroxide.

  • Potassium percarbonate, K 2 C 2 0 6, is obtained in the electrolysis of potassium carbonate at -10 to -15°.

  • Canvas diaphragms were used to prevent the acid formed by electrolysis at the anode from mixing with the cathode liquor, and so hindering deposition.

  • 13,336 of 1894) a rapidly rotating cathode is used in a chloride solution, a porous partition separating the tank into anode and cathode compartments, and the chlorine generated by electrolysis at the anode being recovered.

  • In many of these the application of heat is necessary to bring the substances used into the liquid state for the purpose of electrolysis, aqueous solutions being unsuitable.

  • 30) obtained potassium by the electrolysis of a mixture of potassium and calcium chlorides fused over a lamp. There are here foreshadowed two types of electrolytic furnace-operations: (a) those in which external heating maintains the electrolyte in the fused condition, and (b) those in which a currentdensity is applied sufficiently high to develop the heat necessary to effect this object unaided.

  • But in some cases in which the current is used for electrolysis and for the production of extremely high temperatures, for which the calorific intensity of ordinary fuel is insufficient, the electric furnace is employed with advantage.

  • The reduction is not due to electrolysis, but to the action of carbon on alumina, a part of the carbon in the charge being consumed and evolved as carbon monoxide gas, which burns at the orifice in the cover so long as reduction is taking place.

  • The isolation of the metals sodium and potassium by Sir Humphry Davy in 1807 by the electrolysis of the fused hydroxides was one of the earliest applications of the electric current to the extraction of metals.

  • Sainte Claire Deville working independently obtained aluminium by the electrolysis of the fused double sodium aluminium chloride.

  • The present article deals with processes that involve the electrolysis of aqueous solutions, whilst those in which electricity is used in the manufacture of chemical products at furnace temperatures are treated under Electrometallurgy, although, strictly speaking, in some cases (e.g.

  • For the theory and elemental laws of electro-deposition see Electrolysis; and for the construction and use of electric generators see Dynamo and Battery: Electric. The importance of the subject may be gauged by the fact that all the aluminium, magnesium, sodium, potassium, calcium carbide, carborundum and artificial graphite, now placed on the market, is made by electrical processes, and that the use of such processes for the refining of copper and silver, and in the manufacture of phosphorus, potassium chlorate and bleach, already pressing very heavily on the older non-electrical systems, is every year extending.

  • The chlorine reacts with the caustic soda, forming sodium hypochlorite, and this in turn, with an excess of chlorine and at higher temperatures, becomes for the most part converted into chlorate, whilst any simultaneous electrolysis of a hydroxide or water and a chloride (so that hydroxyl and chlorine are simultaneously liberated at the anode) also produces oxygen-chlorine compounds direct.

  • It is obvious that, with suitable methods and apparatus, the electrolysis of alkaline chlorides may be made to yield chlorine, hypochlorites (bleaching liquors), chlorates or caustic alkali, but that great care must be exercised if any of these products is to be obtained pure and with economy.

  • pp. 198, 329, 43 8) in connexion with the electrolysis of hydrochloric acid.

  • Hermite, which consisted in the production of bleach-liquors by the electrolysis (according to the 1st edition of the 1884 patent) of magnesium or calcium chloride between platinum anodes carried in wooden frames, and zinc cathodes.

  • His system for the disinfection of sewage and similar matter by the electrolysis of chlorides, or of sea-water, has been tried, but for the most part abandoned on the score of expense.

  • Again, anode reactions, such as are observed in the electrolysis of the fatty acids, may be utilized, as, for example, when the radical CH3C02 - deposited at the anode in the electrolysis of acetic acid - is dissociated, two of the groups react to give one molecule of ethane, C 2 H 6, and two of carbon dioxide.

  • Use has been made of electrolysis in tanning operations, the current being passed through the tan-liquors containing the hides.

  • The production of ozone in small quantities during electrolysis, and by the so-called silent discharge, has long been known, and the Siemens induction tube has been developed for use industrially.

  • In Berzelius' system + potassium sulphate is to be regarded as K 2 0.S0 3; electrolysis should simply effect the disruption of the positive and negative components, potash passing with the current, and sulphuric acid against the current.

  • Gold is also attacked when strong sulphuric acid is submitted to electrolysis with a gold positive pole.

  • Other metals which find application in the metallurgy of gold by virtue of their property of extracting the gold as an alloy are lead, which combines very readily when molten, and which can afterwards be separated by cupellation, and copper, which is separated from the gold by solution in acids or by electrolysis; molten lead also extracts gold from the copper-gold alloys.

  • The precipitation is effected by zinc in the form of bright turnings, or coated with lead, or by electrolysis.

  • Siemens and Halske, essentially consists in the electrolysis of weak solutions with iron or steel plate anodes, and lead cathodes, the latter, when coated with gold, being fused and cupelled.

  • The metal has been obtained by electrolysis of a mixture of caesium and barium cyanides (C. Setterberg, Ann., 1882, 211, p. loo) and by heating the hydroxide with magnesium or aluminium (N.

  • The dioxide, 0s0 2, is formed when potassium osmichloride is heated with sodium carbonate in a current of carbon dioxide, or by electrolysis of a solution of the tetroxide in the presence of alkali.

  • Amphiaraus, foreseeing the disastrous issue of the war, at first refused to share in it; he had, however, promised Eriphyle when he married her that, in the event of any dispute arising between her brother and ' See " The Electrolysis of Copper Sulphate in Standardizing Electrical Instruments," by A.

  • Electrolytic or ionic dissociation is the separation of a substance in solution into ions (see Electrolysis; Solution).

  • Davy, inspired by his successful isolation of the metals sodium and potassium by the electrolysis of their hydrates, attempted to decompose a mixture of lime and mercuric oxide by the electric current; an amalgam of calcium was obtained, but the separation of the mercury was so difficult that even Davy himself was not sure as to whether he had obtained pure metallic calcium.

  • Electrolysis of lime or calcium chloride in contact with mercury gave similar results.

  • filr Electrochemie, 1902, p. 8757) obtained the metal of 90% purity by electrolysing calcium chloride at a temperature of about 780°, using an iron cathode, the anode being the graphite vessel in which the electrolysis was carried out.

  • On electrolysis a layer of metallic calcium is formed at the lower end of this rod on the surface of the electrolyte; the rod is gradually raised, the thickness of the layer increases, and ultimately a rod of metallic calcium, forming, as it were, a continuation of the iron cathode, is obtained.

  • The metal as prepared by electrolysis generally contains traces of aluminium and silica.

  • Moissan in 1886 by the electrolysis of pure anhydrous hydrofluoric acid containing dissolved potassium fluoride.

  • Whilst the electrolysis is proceeding, the apparatus is kept at a constant temperature of - 23° C. by means of liquid methyl chloride.

  • During electrolysis, oxygen is evolved at the anode and escapes from the outer vessel, while the sodium deposited in globules on the cathode floats upwards into the iron cylinder, within which it accumulates, and from which it may be removed at intervals by means of a perforated iron ladle, the fused salt, but not the metal, being able to pass freely through the perforations.

  • The hydroxide or caustic soda, NaOH, is usually manufactured from the carbonate or by electrolysis of salt solution (see Alkali Manufacture).

  • Meyer, Ber., 1876, 9, P. 543), C3H7NH 2 +HNO 2 =N 2 +2H 2 O+C 3 H 6; by the electrolysis of the alkali salts of saturated dicarboxylic acids; by the decomposition of 0-haloid fatty acids with sodium carbonate, CH 3 CHBr CH(CH 3) CO 2 H =CO 2 -1-HBr+CH 3 CH :CH CH 3; by distilling the barium salts of acids Cn,H 2, ,,- 2 0 2 with sodium methylate in vacuo (I.

  • Oxidizing agents (Cl, Br, H202, &c.) convert it into potassium ferricyanide (see below), a similar result being attained by the electrolysis of its aqueous solution: 2K 4 Fe(NC)s + 2H 2 0 = 2KOH + H2 + 2K 3 Fe(NC) 6.

  • Moissan found that the oxide resisted reduction by carbon in the electric furnace, so that electrolysis of a fusible salt of the metal must be resorted to.

  • Borchers also used an externally heated metal vessel as the cathode; it is provided with a supporting collar or flange a little below the top, so that the upper part of the vessel is exposed to the cooling influence of the air, in order that a crust of solidified salt may there be formed, and so prevent the creeping of the electrolyte over the top. The carbon anode passes through the cover of a porcelain cylinder, open at the bottom, and provided with a side-tube at the top to remove the chlorine formed during electrolysis.

  • His work included investigations of osmic acid, of the ferrates, stannates, plumbates, &c., and of ozone, attempts to obtain free fluorine by the electrolysis of fused fluorides, and the discovery of anhydrous hydrofluoric acid and of a series of acides sulphazotes, the precise nature of which long remained a matter of discussion.

  • The subject is dealt with in Electrolysis and Electric conduction: § dealt with the relations between the properties of an ideally dilute solution, we now turn to the consideration of the general case where the simplifying assumption of great dilution is not made.

  • The special properties of these solutions are dealt with under Electrolysis and Electric conduction, § In Liquids.

  • Hall, by devising the electrolytic method now in use, inaugurated the present era of industrial electrolysis.

  • If, according to the present method of winning the metal, a bath containing silica as well as alumina is submitted to electrolysis, both oxides are dissociated, and as silicon is a very undesirable impurity, an alumina contaminated with silica is not suited for reduction.

  • Many metals, of which copper, silver and nickel are types, can be readily won or purified by the electrolysis of aqueous solutions, and theoretically it may be feasible to treat aluminium in an identical manner.

  • Of the simple compounds, only the fluoride is amenable to electrolysis in the fused state, since the chloride begins to volatilize below its melting-point, and the latter is only 5° below its boiling-point.

  • This preparation of a chlorine compound suited for electrolysis becomes more costly and more troublesome than that of the oxide, and in addition four times as much raw material must be handled.

  • That this process did not depend upon electrolysis, but was simply an instance of electrical smelting or the decomposition of an oxide by means of carbon at the temperature of the electric arc, is shown by the fact that the Cowles furnace would work with an alternating current.

  • In 1886 he succeeded in obtaining the element fluorine in the free state by the electrolysis of potassium fluoride and anhydrous hydrofluoric acid at a low temperature.

  • It may be prepared by the electrolysis of acidulated water, by the decomposition of water by various metals or metallic hydrides, and by the action of many metals on acids or on bases.

  • Naumann and C. Pistor, Ber., 1885, 18, p. 1647), or by the electrolysis of a dilute solution of caustic soda (C. Winssinger, Chem.

  • Palladium and some other metals are capable of absorbing large volumes of hydrogen (especially when the metal is used as a cathode in a water electrolysis apparatus).

  • Traube, Ber., 1882, 15, p. 659); in the oxidation of zinc, lead and copper in presence of water, and in the electrolysis of sulphuric acid of such strength that it contains two molecules of water to one molecule of sulphuric acid (M.

  • Ann., 1875, 156, p. 466) on electrolysis of the fused chloride, while C. Winkler (Ber., 1890, 23, p. 78) prepared it by heating the oxide with a mixture of magnesium and magnesia.

  • From the filtered solution the thallium is recovered, as such, by means of pure metallic zinc, or by electrolysis.

  • Mallet, Comptes rendus, 1867, 64,' p. 226; 1868, 66, p. 349); by the electrolysis of solutions of sodium hydroxide, using nickel electrodes; by heating calcium plumbate (obtained from litharge and calcium carbonate) in a current of carbon dioxide (G.

  • Norton have prepared it by the electrolysis of the melted chloride (Pogg.

  • - Some of the chlorine manufactured (practically only such as is obtained by the electrolysis of chlorides) is con densed by cold and pressure into liquid chlorine.

  • Most of the chlorate of potash is now prepared by electrolysis of potassium chloride (see below).

  • Electrolitic Alkali Manufacture In theory by far the simplest process for making alkalis together with free chlorine is the electrolysis of sodium (or potassium) chloride.

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