Extending his investigations to the currents produced by batteries, he found that the total voltaic heat generated in any circuit was proportional to the number of electrochemical equivalents electrolysed in each cell multiplied by the electromotive force of the battery.
Now, we know that the number of electrochemical equivalents electrolysed is proportional to the whole amount of electricity which passed through the circuit, and the product of this by the electromotive force of the battery is the work done by the latter, so that in this case also Joule showed that the heat generated was proportional to the work done.
In 1806 Sir Humphry Davy proved that the formation of acid and alkali when water was electrolysed was due to saline impurities in the water.
The ore was crushed roasted, and leached with sulphuric acid (with or without ferric sulphate); the solution was purified and then electrolysed for zinc with lead anodes and with a currentdensity of 5 amperes per sq.
When an aqueous solution of the salt of an alkali metal is electrolysed, the Date.
So early as 1851 a patent was taken out by Cooke for the production of caustic alkali without the use of a separate current, by immersing iron and copper plates on opposite sides of a porous (biscuit-ware) partition in a suitable cell, containing a solution of the salt to be electrolysed, at 21 0 -65° C. (70 -150° F.).
When an alkaline chloride, say sodium chloride, is electrolysed with one electrode immersed in a porous cell, while caustic soda is formed at the cathode, chlorine is deposited at the anode.
The same inventor has patented the application of electrolysed chlorides to the purification of starch by the oxidation of less stable organic bodies, to the bleaching of oils, and to the purification of coal gas, spirit and other substances.
If a solution of potassium acetate be electrolysed the products are ethane, carbon dioxide, potash and hydrogen; in a similar manner, normal potassium succinate gives ethylene, carbon dioxide, potash and hydrogen; these reactions may be represented: CH 3 ï¿½CO 2;K CH 3 CO 2 K' CH 2 ï¿½CO 2 1K CH 2 CO 2 K' --> I + + I I -i iI + CH 3 ï¿½CO 21 K CH 3 CO 2 K' CH 2 ï¿½CO 2 iK CH 2 CO 2 K' By electrolysing a solution of potassium ethyl succinate, KO 2 Cï¿½(CH 2) 2 CO 2 C 2 H 5, the KO 2 Cï¿½ groups are split off and the two residues ï¿½(CH 2) 2 CO 2 C 2 H 5 combine to form the ester (CH2)4(C02C2H5)2.
One process depends upon the fact that, with a suitable current density, if a very dilute solution of silver nitrate be electrolysed between an auriferous silver anode and a silver cathode, the silver of the anode is dissolved out and deposited at the cathode, the gold remaining at the anode.
The amorphous metal also results when the chloride is heated with sodium; the oxide reduced with magnesium; or when fused potassium zircono fluoride is electrolysed (Wedekind, Zeit.
Bunsen (Ann., 1854, 92, p. 248) was more successful when he electrolysed calcium chloride moistened with hydrochloric acid; and A.
1902, 35, p. 3612) employed a mixture of calcium chloride (ioo parts) and fluorspar (16.5 parts), which was fused in a porcelain crucible and electrolysed with a carbon anode and an iron cathode.
Soc., 1856, p. 30) electrolysed an equimolecular mixture of potassium and calcium chlorides (which melts at a lower temperature than potassium chloride) also between carbon electrodes; whilst Castner's process, in which caustic potash is electrolysed, is employed commercially.
When melted in a current of hydrogen or electrolysed in the same condition, a dark blue mass is obtained of uncertain composition.
Bunsen, in 1852, electrolysed fused magnesium chloride in a porcelain crucible.
It has been found, however, that molten cryolite and the analogous double fluoride represented by the formula Al 2 F 6.2NaF are very efficient solvents of alumina, and that these solutions can be easily electrolysed at about 800° C. by means of a current that completely decomposes the oxide but leaves the haloid salts unaffected.
The electrolyte, when too impure for further use, is commonly recrystallized, or electrolysed with insoluble anodes to recover the copper.
Bunsen in 1854 electrolysed a thick paste of barium chloride and dilute hydrochloric acid in the presence of mercury, at 10o C., obtaining a barium amalgam, from which the mercury was separated by a process of distillation.
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.