SOLUTIONS AS A FUNCTION OF TEMPERATURE 165 



of the maximum increases slowly. Similar curves have been found for 

 solutions in ethylamine, methylamine, and sulphur dioxide. 



While the complete conductance-temperature diagram is not known 

 for most solvents, sufficient data exist to indicate that it is a general 

 property of electrolytic solutions to exhibit an increasing positive tem- 

 perature coefficient at high concentrations. In certain cases this coeffi- 

 cient may be very great. In other cases the coefficient at lower concen- 

 trations is negative, decreasing with the concentration and becoming 

 positive at higher concentrations. In the following table is given a list 

 of temperature coefficients for substances dissolved in the liquid halogen 

 acids. 18 The coefficients are positive unless otherwise indicated. 



TABLE LIX. 



TEMPERATURE COEFFICIENT a X 100 OF SOLUTIONS OF ELECTROLYTES IN 



DIFFERENT SOLVENTS. 



Hydrogen Bromide. 



Electrolyte V x a V 2 a, V, a, 



Acetic Acid 4.30 2.62 0.571 2.72 



Butyric Acid 4.18 2.68 0.817 3.70 



Iso-valeric Acid 4.37 2.45 0.729 3.96 



Benzoic Acid 8.82 0.53 2.38 0.72 1.14 0.89 



Metatoluic Acid 5.85 0.15 1.83 0.93 



Hydroxybenzoic Acid . . . 18.4 1.00 1.36 2.15 



Methyl Alcohol 1.75 2.5 1.25 4.2 



Metacresol 15.0 7.71 1.00 + 1.16 



Thymol 43.6 .47 7.34 0.00 



Alphanaphthol 51.6 2.26 18.0 0.30 



Hydrogen Chloride. 



Propionic Acid 11.8 2.15 2.5 2.91 



Butyric Acid 50.1 2.80 0.792 3.27 



Methyl Alcohol 2.91 1.21 1.06 2.68 



Ethyl Alcohol 4.66 3.9 0.591 4.0 



Butyl Alcohol 5.07 5.23 0.574 6.5 



Resorcin 137.0 1.33 6.29 0.00 0.539 +1.3 



With the exception of solutions of thymol and alphanaphthol in 

 liquid hydrogen bromide, the positive temperature coefficients through- 

 out increase with increasing concentration. For lack of more compre- 

 hensive experimental data regarding the temperature coefficient of the 

 substances named, it is impossible to hazard a guess as to the reason for 

 the decrease of the positive temperature coefficients in the case of the 

 solutions of these two substances. Particularly notable is the high nega- 



Archibald, Journal de Chimie Physique 11, 741 (1913). 



