4.84: TRANSACTIONS OF SECTION B. 
Il. On the Influence of Temperature on the Conductivity of Electrolytes. 
1. The influence of temperature on the conductivity of electrolytes may be 
expressed by the general equation 
du_ (. dv di 
dt “\’ ae” at 
where 7=concentration of the ions, »=mean rate of migration of positive and 
negative ions, ¢= temperature, and c= constant. 
If the effect of change of temperature on the rate of migration is the reverse 
of that on the degree of dissociation, a maximum in the temperature-conductivity 
curve is to be expected. 
2, It may be deduced that, for a given electrolyte, the smaller the dielectric 
constant of the solvent the lower must lie the temperature of maximum con- 
ductivity. 
3. These deductions are confirmed by the results of previous experiments on 
solutions in water,' methyl? and ethyl alcohols, ammonia* and sulphur dioxide,* 
and especially by the results of the present investigation on solutions in pyridine. 
‘The influence of temperature on the electric conductivity of solutions in pyridine 
has been determined for a number of acids and pseudo-acids, as well as for silver 
nitrate. The temperature of maximum conductivity is well marked, and the 
curves have been followed up to and beyond this point. 
4, The curves are represented closely by the parabolic equation p, = y,(1 + d¢ + ct”) 
and the theoretically deduced expression @= t~F+_ is taken as a measure of the 
p(t 7)? 
temperature effect. 
5. The observation of Walden and Centnerszwer, that for solutions in liquid 
sulphur dioxide the temperature of maximum conductivity is higher, the greater 
the conductivity, has not been confirmed for solutions in pyridine. 
6. The comparatively rapid decrease in the degree of dissociation with increase 
in temperature may partly explain the fact that numerous substances which at 
ordinary temperatures yield good conducting pyridine solutions appear, according 
to boiling-point determinations, to be undissociated, 
IL], Abnormally High Values of Ionic Conduetivity.° 
Solutions of salts which contain either the same cation or the same anion as 
the solvent itself (pyridonium salts in pyridine, formates in formic acid, acetates 
in acetic acid, and probably bromides in hydrobromic acid and sulphates in 
sulphuric acid) show in these solvents an abnormally high conductivity in com- 
parison with all other salts. Since all salts are dissociated to approximately the 
same extent, the abnormally high values of the conductivity of the first class can 
only be explained by assuming an abnormally high value for the rate of migration 
of those ions which the salt has in common with the solvent. 
This abnormal value of the rate of migration is, however, only an apparent 
one. The ions of such salts react with the solvent with exchange of a labile 
hydrogen atom. 
MONDAY, AUGUST 5. 
The following Papers and Reports were read :— 
1. The Applications of Grignard’s Reaction. By ALEX. MACKENZIE, 
M.A., D.Sc., Ph.D.—See Reports, p. 273. 
! Noyes and Coolidge, Zeitschr. phys. Chem., 46, 323. 
2 Kraus, Phys. Review, 18, 40. 
3 Amer. Chem. Journ., 24, 83. 
4 Walden and Centnerszwer, Zeit. phys. Chem., 39, 513. 
5 Cf. Danneel, Zit. iin Hlektrochem., 11, 249. 
