An application to electrolytes of the hydrate theory of solutions / by T. Martin Lowry.

  • Martin Lowry
Date:
[1905]
Catalogue details

Licence: In copyright

Credit: An application to electrolytes of the hydrate theory of solutions / by T. Martin Lowry. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    explained on the same hypothesis as that which furnishes an explanation of the conductivity of solutions, namely, that in order to prevent the equalisa- tion of ionic charges, a protective menstruum is necessary, and it appears that this menstruum may be furnished by the same substance as that which also undergoes ionisation.” If, however, the ionisation of aqueous solutions be explained in terms of the hydrate theory as due to the association of the ions with the molecules of the solvent, the analogous explanation for fused salts would be that the ions are associated with the neutral molecules of the salt. Thus in the case of fused potassium chloride the liquid would contain ions such as K(KC1), Cl(KCl)^ corresponding to the hydrates K(HaO)* 6i(H2OV postulated in aqueous solutions. The effective cause of ionisation would therefore again be found in the tendency of the simple ions to associate with the molecules of the solvent, and the extent of ionisation would be determined by the relative stability of the molecular and of the ionic complexes. (3) Direct evidence of the tendency, which exists even in aqueous solu- tions, to form ionic complexes of the type formulated above, has been obtained by Abegg and Bodlander and other workers in the field of “ Electro-affinity.” As a result of their investigations it has become clear that double salts and complex ions are formed, not only in the case of substances such as the ferrocyanides, argenticyanides and platinichlorides 4KCN + FeC2N2 K4FeC6N6 <=> 4K | FeC6N6 KCN 4- AgCN KAgC2N2 K | AgC2N2 + — — 2NaCl + PtCl4 Na2PtCl6^=^2Na[ PtCl4 but also in the case of divalent chlorides, such as those of mercury, cadmium, calcium, etc.: 2NaCl + HgCL Na2HgCl4 <=> 2Na | HgCl4 2KCI +CdCl2 ^=> K2CdCl4 2K I CdCl4 + ~ — 2KCI + CaCl2 ^=> K2CaCl4 2IC | CaCl4 It has further been shown that aqueous solutions of single salts may behave in a similar manner and yield complex rather than simple ions thus :— 2CoC12 [CoCoC14] <=> Co I CoCl4 2CdCl2^=>[CdCdCl4] <=> Cd | CdCl4 + + ~ ~ 2CuC\2^> [CuCuC14] <=> Cu I CuCl4 The formation of such complexes, which are of exactly the same type as those postulated in the case of fused salts, affords the only satisfactory explanation of a number of instances in which a metal travels during electro- lysis in the opposite direction to the current. It may be added that the formation of complex ions also affords an explanation of the fact that ionisa- tion is not always accompanied by an abnormally great osmotic pressure;
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