An effort to refute the arguments advanced in favour of the existence in the amphide salts, of radicals : consisting, like cyanogen, of more than one element / by Robert Hare.

  • Hare, Robert, 1781-1858.
Date:
1842
Catalogue details

Licence: Public Domain Mark

Credit: An effort to refute the arguments advanced in favour of the existence in the amphide salts, of radicals : consisting, like cyanogen, of more than one element / by Robert Hare. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    85. I cannot conceive, that in any point of view the complicated and '■'■confused'1'' results of the experiment of Daniell with electrolytes separated by membranes, are rendered more intelligible by supposing the existence of salt radicals. I cannot perceive that the idea that the anion in the sulphate is oxysulphion, makes the explanation more satisfactory than if we suppose it to be oxygen. Were a solution of copper subjected to electrolysis alone, if the oxide of copper were the primary object of the current, the result would be analogous to the case of sodium, excepting that the metal evolved at the cathode, not decomposing water, would appear in the metallic form. If water be the primary object of attack, the evolution of copper would be a secondary effect. 86. It is remarkable, that after I had written the preceding interpretation of Daniell's experiments, I met with the following deductions stated by Mat- teuchi, as the result of an arduous series of experiments, without any refer- ence to those of Daniell above mentioned. It will be perceived that these deductions coincide perfectly with mine. 87. I subjoin a literal translation of the language of Matteuchi from the Annales de Chimie et de Physique, tome 74, 1840, page 110 :— When salt, dissolved in water, is decomposed by the voltaic current, if the action of the current be confined to the salt, for each equivalent of water decomposed in the voltameter, there will be an equivalent of metal at the negative pole, and an equivalent of acid, plus an equivalent of oxygen, at the positive pole. The metal separated at the negative pole will be in the metallic state, or oxidized according to its nature. If oxidized, an equiva- lent of hydrogen will be simultaneously disengaged by the chemical decom- position of water. 88. Thus it seems, that the appearance of acid and oxygen at the anode, and of alkali and hydrogen at the cathode, which has been considered as requiring the simultaneous decomposition of two electrolytes upon the here- tofore received theory of salts, has, by Matteuchi, been found to be a result requiring the electrolysis of the metallic base only, and, consequently, to be perfectly reconcilable with that theory. 89. In fact I had, from the study of Faraday's Researches, taken up the impression, that the separate appearance of an acid and base, previously forming a salt, at the voltaic electrodes, was to be viewed as a secondary ef- fect of the decomposition of the water or the base; so that acids and bases were never the direct objects of electrolytic transfer. Of Liebig's Principles so called. 90. Under the head of the theory of organic acids, in Liebig's Trea- tise on Organic Chemistry, we find the following allegations dignified by the name of principles. Manifestly they must tend to convey a false im- pression to the student, that hydrogen has a peculiar property of creating a capacity for saturation, instead of being only the measure of that capacity, as is actually true, and likewise that in this respect it differs from any other radical. 91. The allegations to which I refer are as follows, being a literal trans- lation from the French copy of the Traite of Liebig, page 7 :— The hydrated acids are combinations of one or more elements with hy- drogen, in which the latter may be replaced wholly or in part by equiva- lents of metals. The capacity of saturation depends consequently on the quantity of hy- drogen which can be replaced.