64 



WORK OF J. N. PEARCE. 



Table 46.- 



-Strontium Chloride Data for Freezing-point and Conductivity Measurements, Specific 



Gravity, and Hydrates. 



MAGNESIUM CHLORIDE. 



The value of /*, for magnesium chloride was found to be 123.95. The values of 

 V show a minimum at 0.25 normal, while the values of H begin to be constant at 

 0.5 normal. Magnesium chloride differs from the other chlorides thus far discussed 

 in that its values for M show no minimum, but increase regularly with increasing 

 concentration. (See table 47.) 



It should be noticed also that magnesium chloride has greater power to combine 

 with water than any of the halides of the calcium group. Especially is this the 

 case in the dilute solutions, where the ions predominate. That this is not due to 

 hydrolysis and the liberation of the free mineral acid is evident from the fact that 

 the molecular lowering of the freezing-point in the dilute solutions is in every case 

 considerably higher than the calculated lowering. As we shall see later, in our 

 study of the acids just the reverse was found to be the case. The curves for this 

 salt are found in figs. 22 and 23. 



BARIUM CHLORIDE. 



A nearly saturated solution of this salt was first made. This was diluted to con- 

 venient concentration, and equal portions were precipitated and weighed as barium 

 sulphate. Owing to the slight solubility of this salt, we did not attempt to work 

 with concentrations greater than 0.4 normal. 



