Theoretical Discussion. 
445 
that there are many solvents of this nature which do react 
with the dissolved substance, and yet which do not yield solu¬ 
tions that conduct electricity. Picric acid reacts with benzene 
but the resulting solution does not conduct electricity. Hence 
chemical combination of the dissolved substance with the sol¬ 
vent may take place and yet the solutions need not necessarily 
conduct. Werner has isolated and analyzed a large number of 
products of pyridine and piperidine, among those of other or¬ 
ganic solvents, with salts of the heavy metals. From the boil¬ 
ing point determinations, the molecular weights of these salts 
seem to be very slightly influenced by their union with the 
solvent. This is analogous to the fact, that salts which crys¬ 
tallize from an aqueous solution with water of crystallization, 
yield the same molecular weights whether dissolved in the an¬ 
hydrous form or with their water of crystallization. Werner 
perhaps sums up his idea best in the following manner: “ Da 
nicht bezweifelt werden kann, dass in bestimmten organischen 
Losungen hydratahnliche Additions-producte von Lbsungsmit- 
tel und Metallsalz als bestandige Verbindungen gelbst sind, so 
muss auch angenommen werden, dass bestimmte Hydrate in 
den wasserigen Losungen enthalten sein konnen; wenn im 
ietzterem Fall eine elektrolytische Dissoziation eintritt, so 
entstehen nicht Metal lionen, sondern an deren Stelle treten 
ionisierte Metallwasserradikale. ” Carrara thinks that the 
union of solvent and dissolved substance accounts for the slight 
conductivity in certain cases. The low values for ^ in the case 
of acetone solutions of HC1 and LiCl he attributes to this fact. 
It has been pointed out by Ciamician 1 that the dissociative 
power of a solvent depends principally upon its chemical struc- 
ure. That is, compounds of the same chemical type, for ex¬ 
ample, of the HOH type, yield solutions that conduct well. 
This is true in the case of alcoholic solutions, which are not 
the only class of compounds that possess dissociative power; 
as has already been pointed out. In general, however, if one 
member of a particular type of compounds (e. g. nitriles), 
yields solutions that conduct, it has been found that other 
members also possess this property; and if a member of some 
1 fcsj eit. phys . Chem ., 6, 403; 1890. 
