4 CONDUCTIVITY AND VISCOSITY IN MIXED SOLVENTS. 



AMMONIA. 



Several years ago Cady l noticed that solutions of salts in liquid ammonia 

 conduct the current. Goodwin and Thomson 2 made some measurements of 

 the conductivity of such solutions, while at work on the dielectric constant 

 of liquid ammonia. The most elaborate work, however, on this subject is 

 that of Franklin and Kraus. 3 They measured the conductivity of potassium 

 bromide and nitrate, sodium bromide and bromate, ammonium chloride and 

 nitrate, silver iodide and cyanide, besides other inorganic salts, and organic 

 compounds over very great changes in dilution. 



A direct comparison of the values of the conductivities in liquid ammonia 

 with similar values in water, shows that the former are much larger than the 

 latter. This, however, does not necessarily mean a larger dissociation, since 

 the conductivity is dependent on two factors, namely, the dissociation and 



the velocity of the ions. The percentage dissociation (= ) is larger 



V /*/ 



in water than in ammonia, and hence the large conductivity of solutions 

 in liquid ammonia is due rather to the high velocity of the ions than to the 

 large number present. 



NITRIC ACID. 



The only work on solutions in nitric acid is that of Bouty, 4 who has meas- 

 ured the conductivity of certain alkaline nitrates when dissolved in nitric 

 acid. The conductivities are nearly as large as in water, but the work is too 

 fragmentary to permit making comparisons between the dissociating power 

 of nitric acid and of water. The former is, however, in all probability, a 

 good dissociant. 



SULPHUR DIOXIDE. 



Walden and Centnerszwer 5 published the results of an extensive investiga- 

 tion on sulphur dioxide as a solvent. This is an extension of the older work 

 of Walden. 8 They investigated the conductivity of nineteen salts, consisting 

 of iodides, bromides, chlorides, and sulphocyanates of inorganic and organic 

 bases. They show, first, that while in aqueous solution the molecular con- 

 ductivities at 25 of monobasic halogen salts generally lie between 100 and 

 140, the corresponding values in sulphur dioxide vary between 3 and 157; 

 second, that Kohlrausch's law of the independent migration velocities of 

 the ions does not hold for solutions in sulphur dioxide. They have also 

 shown by a series of conductivity measurements at different temperatures 

 between -78 and 157 (the freezing-point and critical temperature of 



1 Journ. Phys. Chem., 1, 707 (1896). " Compt. rend., 106, 595 (1888). 



2 Phys. Rev., 8, 38 (1899). 6 Ztschr. phys. Chem., 39, 513 (1902). 



3 Amer. Chem. Journ., 23, 277; 24, Ber. d. chem. Gesell., 32, 2862 (1899). 

 83 (1900). 



