350 



240 



230 



220 



210 



200 



190 



180 



170 



160 



5s 150 



u 



3 

 T> 

 c 

 o 

 o 



140 



130 



CONDUCTIVITIES OF ORGANIC ACIDS IN ETHYL ALCOHOL. 65 



be expected, and that the Ostwald dilution law could not be applied 

 to the mixtures containing much alcohol. 



In 1894 Schall 1 determined the conductivity of oxalic, dichloracetic, 

 picric, and hydrochloric acids in methyl alcohol, in ethyl alcohol, 

 in ethyl alcohol-water mixtures, and in isobutyl alcohol. He con- 

 cluded from his results that 

 molecular conductivity is much 

 less in the alcohols than in 

 water, and that the acids be- 

 have very differently in alcohol- 

 water mixtures than in the pure 

 solvents; some acting just the 

 opposite from what might be 

 expected from their behavior in 

 the pure solvents. For in- 

 stance, picric acid gives a much 

 higher, and the others much 

 lower, conductivity values in 

 water-alcohol mixtures than in 

 the pure alcohol. 



A careful piece of work on 

 the conductivity of certain 

 organic acids, acetic, mono- 

 chloracetic, dichloracetic, tri- 

 chloracetic, and succinic acids, 

 and of hydrochloric acid in 

 absolute alcohol at 18 was 

 carried out, in 1894, by Wil- 

 dermann. 2 The alcohol was 

 freed from aldehyde by treat- 

 ment with silver nitrate, and 

 'from water by heating with 

 calcium oxide. Great care 

 was exercised in protecting 

 the alcohol from the air, and 

 a special apparatus was con- 

 structed for drawing a meas- 

 ured quantity of alcohol out of 

 the supply bottle directly into 

 the conductivity cell, which had a capacity of about 25 c.c. In order 

 to make his minimum points on the bridge more distinct, Wildermann 

 employed a graphite resistance rheostat which he constructed and 

 standardized against a known resistance. He states that his con- 

 ductivity cells had to be washed with running water for about 8 to 10 



o no 



o 



120 



100 



30 40 50 60 70 

 Percentage alcohol 



80 90 100 



FIG. 21. Monobromacetic acid. 



!Zeit. phys. Chem., 14, 701 (1894). 



*Ibid., 14, 231 (1894). 



