being the case can be obtained from the behaviour of a carbotype solute in an acid or oxime if the acid or oxime is associated to a double molecule in the liquid state. There is, however, evidence that during the association of an acid or oxime in a carbotype solvent, the solvent exerts a specific influence on the association of a nature which has not been explained. If the solvent merely acted as a diluent, the mass law should apply to the dissociation of the double molecules, as in gaseous dissociation. Auwers (Zeitsch. physikal. Chem., 1907, 60, 385) has shown that with acids and oximes this is by no means the case, C2/C decreasing very rapidly with concentration. The data obtained in the present investigation are more suitable for such calculations than those used by Auwers, since the determinations were made isothermally; the results of calculation are, however, similar. The anilides also show large variations in the value of C4/C. Since there is direct and fairly conclusive evidence of mutual association between alcohols and phenols and a carbotype, it is reasonable to ascribe the influence of the carbotype solvent on the association of the acids, oximes, and anilides to the same cause. The position of the maximum association of dimethyl tartrate in benzene at or near equimolecular concentration evidently indicates that in this instance association of solute and solvent takes place at the same rate. Although there is no evidence as to the rate of association of the solvent in other instances, it is not unreasonable to assume, for purposes of further investigation, that in a solvent which is non-associated in the liquid state, association of solvent and solute is in general equal. The cause of mutual association of solute and solvent obviously cannot be chemical, as anything in the nature of combination between the two constituents, in concentrated solution, is impossible (p. 425). The only adequate explanation which has occurred to the author is that it is electrical in character.* It seems reasonable to suppose that the association begins in the oxytype substance, whether this is functioning as solvent or solute. If we imagine that for each molecule entering into an aggregate a definite quantity of electricity passes to the carbotype substance, causing in it an association equal to that in the oxytype, and that this goes on until an equilibrium is attained, depending on the temperature, concentration, pressure, and nature of the solvent and solute, this would account for the fact that dimethyl tartrate and benzene appear to associate at the same rate. * That association may be due to electrical, not chemical, forces has already been suggested by Turner and English (T., 1914, 105, 1793). If we assume that the charge that passes when a substance |
