50 



CONDUCTIVITY AND VISCOSITY IN MIXED SOLVENTS. 



TABLE 27. Comparison of conductivities. 



From the data given in table 27, it is evident that calcium nitrate in no 

 case exhibits the minimum. The conductivities are always less than the 

 proper average. 



The relation found by Wakeman, 



= const, does not hold in the 



p(100 - p) 

 cases thus far studied; nor does that found by Cohen. 



HYDROCHLORIC ACID. 



In the study of hydrochloric acid the solutions were prepared as follows : 

 Into a portion of the solvent, kept cool by ice, dry hydrochloric-acid gas was 

 conducted. This was obtained by allowing concentrated sulphuric acid to 

 drop slowly from a dropping-funnel into pure, aqueous, hydrochloric acid. 

 The gas was dried by passing through gas-washing bottles containing con- 

 centrated sulphuric acid. The vessel containing the solvent into which the 

 gas was passed, was protected from extraneous moisture by a drying-tube 

 containing phosphorus pentoxide. 



The strength of the original solution was determined volumetrically by 

 means of a standard solution of ammonium hydroxide, methyl orange being 

 used as the indicator. From this solution the dilutions were made. Control 

 determinations were carried out in a number of cases, since only the fairly 

 dilute solutions in mixtures and in pure methyl alcohol were found to be stable. 



The composition of the 69.75 per cent mixture was determined by means 

 of its specific gravity. 



