402 TRANSACTIONS OF SBOTION B. 



4. The Molecular State of Salts in Solution, 

 By W. E. S. Turner and J. D. Cauwood. 



At the 1910 meeting of the Association, one of us demonstrated that the 

 haloid salts of organic ammonium, sulphonium, and oxonium bases were highly 

 associated in a neutral solvent, e.g., chloroform, and evidence was tendered to 

 prove that salts in general are complex molecular substances. Subsequent 

 investigations have brought within the scope of these conclusions metallic salts, 

 whilst the effect of the solvent has also been thoroughly tested. As the salts 

 hitherto employed have been the haloid salts almost entirely, the general con- 

 clusions would be greatly strengthened if it could be shown that salts of acids 

 other than the haloids are also associated. 



For the purpose of this investigation, therefore, a number of new salts have 

 been prepared, including tetrapropylanimonium fluoride, chlorate, bromate, 

 iodate, sulphate, thiocyanate, oxalate, and benzoate. All of them have high 

 molecular weights in chloroform. Thus, the observed molecular weight of the 

 thiocyanate in 4 per cent, solution is nearly seven times the value for the simple 

 formula. 



At the same concentration (25 milligramme molecules per 100 c.c. of solvent), 

 the degree of association increases in the order : iodate, oxalate, chloride, 

 bromide, bromate, chlorate, sulphate, iodide, benzoate, nitrate, periodide, thio- 

 cyanate, fluoride. 



5. lonisation in Solvents of Low Dielectric Constant. 

 By W. E. S. Turner. 



In extension of previous work on conductivity in solvents of low dielectric 

 constant, Sachanov ' has found that the conductivity of a mixture of electrolytes 

 exceeds that of the sum of the conductivities of the single electrolytes by an 

 amount which is greater the lower the dielectric constant of the solvent. From 

 his results, he argues that in solvents of the type used the degree of dissociation 

 of one electrolyte is materially increased by a second one added. 



This interpretation is capable of test by freezing or boiling-point tests on 

 the solutions. Experiments on solutions in chloroform, one of the solvents used 

 by Sachanov, show that the salts tetrapropylammonium iodide, diethyl- 

 ammonium chloride, triethylammonium bromide, phenylethyl- and phenyldiethyl- 

 ammonium chloride and iodide, so far from causiog increased dissociation when 

 dissolved in pairs, have just the reverse effect, producing an increased degree of 

 association. That is to say, Sachanov's interpretation is incorrect, and, whereas 

 in water the molecular conductivity increases as the average size of the electro- 

 lyte molecules decreases, in solvents of low dielectric constant the reverse is the 

 case. 



This conclusion is in harmony with several phenomena previously pointed 

 out by the writer," and also with the fact that the conductivity in solvents of 

 low dielectric constant increases as the molecular size of the solute increases. 



■ Zeitsch. physikal. Chem. 1914, 87, 441. 

 =* Trans. Chem. Soc. 1911, 99, 880. 



