VISCOSITY AND CONDUCTIVITY. 



69 



II KIinC 2 H 5 OH 



III Li NO 3 



IV LiCl 



V Fluidity Curve 



IV 



Formulated, the hypothesis is expressed by the relation ^ = constant, 



x 



or ^ = constant, where the symbols have the usual significance. This be- 

 et 



comes, when fi v = p.oo, /* 17 = constant. 



The meaning of the term "comparable equivalent solutions" needs to be 

 defined. In comparing aqueous solutions those of the same normality (con- 

 taining equal gram-molecules of electrolyte in equal volumes) are strictly com- 

 parable. It is evident that this is not the case when, for example, we come 

 to compare solutions of the 

 same electrolyte in different 

 solvents. In order to be 

 strictly comparable, the so- 

 lutions must contain the same 

 number of gram-molecules of 

 electrolyte dissolved in the 

 same number of gram-mole- 

 cules of the different solvents, 

 or equal weights of the 

 (same) electrolyte dissolved 

 in volumes of the solvents 

 which are proportional to 

 the molecular volumes of 

 the solvents in question. 

 It is obvious that this is the 

 only proper basis of com- 

 parison. 



To illustrate, comparable 

 solutions in water and in 

 methyl alcohol would be 

 those containing the same 

 weight of electrolyte dis- 

 solved in 18 volumes of 

 water and 40 volumes of 

 methyl alcohol, because the molecular volume of water is 18, and that of 

 methyl alcohol approximately 40. The volumes compared should always 

 be in the ratio 18 (of water) to 40 (of methyl alcohol). Similarly, in the case 

 of methyl and ethyl alcohols, the volumes would be as 40 to 57.5. 



In the first place we have plotted (fig. 15) the variation in the fluidity of 

 methyl and ethyl alcohols with temperature, making the different fluidities 

 ordinates and the different temperatures abscissae. Plotted with these, for 

 the sake of comparison, are the conductivities of various binary electrolytes 



33 



o 





30- 



20- 



10 



I Fluidity Curve 



II LiN0 3 V = 256 



III Nal v=256 



IV NH 4 Br J>=256 

 V KI v=25G 



VI LiCl 



10 



20 30 



Temperature 



FIG. 15. COMPARISON OF CONDUCTIVITY 

 AND FLUIDITY. 



