Page:Outlines of Physical Chemistry - 1899.djvu/282

 264 OUTLINES OF PHYSICAL CHEMISTRY

In aqueous solution this first action seems quite generally to be completely accomplished, and the second proceeds to an extent which depends on the nature of the dissolved sub- stance and on the dilution. But in another solvent, such as methyl alcohol, acetone, or acetonitrile, it is possible that the decomposition only occurs after the dissociation, and that the latter is, at least partially, exercised on the complex particles. If this supposition be true, then the electrolytic decomposition of a salt M 2 K 2 1 does not always take place in the same manner.

In aqueous solution the decomposition precedes the dissociation

+ - + -

and the simplified molecules MB give the ions M and R. In

organic solvent solution, on the contrary, the substance might

be only slightly decomposed and behave as if it were constituted

+ — — +

2. The organic solvents capable of forming conducting solu- tions are generally characterised by a more or less pronounced reactivity. 3 This is quite evident in the case of the alcohols, phenols, acids, and other substances of the water-type. It is less so, yet not less real, for certain liquids which contain no hydroxyl but typical hydrogen atoms replaceable by metals or organic

Let us now pass on to the difficulty referred to above, and let

��1 For crystalline salts it has been shown that the particle is often bimolecular.

2 For a given electrolyte the speed of the ions does not require to be the same in different solvents, for not only is the composition of the ions subject to variation (as here shown), but their ease of transportation may be influenced by the degree of viscosity of the solvent.

8 It may be added that they are also characterised by a high association factor (Ramsay, Traube) and by a large dielectric con- stant (Nernst). On the dielectric constant see Nemsfs publications ('Berichte der koniglichen Gesellschaft der Wissenschaften in Gottingen,' 1893), and those of Drude (' Zeitschrift fur physik. Chem.,, 23).

4 In the ketones the hydrogen atoms attached to the carbon next to the GO group play this particular part, as Claisen has shown.

5 Nitroethane has the character of an acid and forms salts which can be isolated.

6 The polymerising action of sodium on nitriles seems to be due to the transitory formation of metallic derivatives (see V. Meyer and Jacobsorts * Organische Chemie,' p. 299).

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