108 



HYDRATES IN AQUEOUS SOLUTION. 



and then becomes less and less, both with increase in the dilution and with 

 increase in the concentration of the solutions. This is probably connected 

 in some way with the fact that with the non-electrolytes we have only mole- 

 cules present, while in solutions of electrolytes we have both molecules and 

 ions present. The curve of hydrates for fructose is given in fig. 61. 



TABLE 90. FRUCTOSE. 



MANNITE. 



Mannite, on the other hand, has very little power to combine with water 

 at any of the dilutions at which work could be done. On account of its 

 comparatively slight solubility, however, we could not work at any consid- 

 erable concentration. A comparison of column L' with column L, table 91, 

 shows that this substance gives molecular lowerings of the freezing-point of 

 water that are only slightly greater than the theoretical lowering. Further, 

 there is no apparent regularity in the difference between the value found 

 and the calculated value. The amount of hydration is so slight that it 



was not even calculated. 

 are plotted in fig. CO. 



The values of , table 91, for this substance 

 m 



