92 



Studies on Solution. 



In table 53 a comparison is made of the conductances and disso- 

 ciation of these nitrates in formamid with similar results in water as 

 the solvent. While the two sets of results are based on different 

 schemes of dilution (M/10 and M/8), the two concentrations are 

 sufficiently close together to permit a general comparison. From the 

 data in the table it appears that the molecular conductivity values for 

 these nitrates in formamid are much smaller than in water, although the 

 order of increasing conductivity is the same in both solvents. 



The greater dissociating power of formamid as compared with water 

 is also shown by the table. It is further illustrated by the fact that 

 complete dissociation is reached by these salts at much lower dilution 

 than in water. For example, sodium nitrate is completely dissociated 

 in formamid at M/800, while in water this is not reached until M/2048. 



TABLE 53. Comparison of the Conductivity and Dissociation of the Alkali and 

 Alkaline Earth Nitrates in Formamid and in Water at 25 C. 



Lithium nitrates crystallize with water of crystallization, while 

 sodium, potassium, and ammonium nitrates do not. According to 

 the theory of Jones and others, this is an indication that the lithium 

 ion is more solvated in solution than are the ions of sodium, potassium, 

 or ammonium. The effect of such solvation is that lithium ions move 

 more slowly than those of the other alkali ions, and consequently the 

 conductivities are much smaller. The solvate theory is a plausible ex- 

 planation for the smaller conductivity values of lithium salts, regardless 

 of the much smaller mass and atomic volume of lithium as compared 

 with the other alkali metals. 



The conductivities of the nitrates of barium, strontium, and calcium 

 in formamid are analogous in every respect to the conductivity 

 phenomena of these salts in water i. e., they show evidence for the 

 formation of complexes with the solvent. As an indication of this, the 

 temperature coefficients of conductivity expressed in conductivity 

 units are higher for these salts than for the alkali nitrates, which have 



