THE ACTION OF NEUTRAL SALTS 



105 



The failure to recognize the buffer character of salts, like the 

 acetates, citrates, and tartrates, has led to the error of the Hof- 

 meister ion series. In reality we find our valency rule confirmed 

 whereby all salts with an anion of the same valency have about 

 the same relative depressing effect on the viscosity of a gelatin 

 chloride solution if the pH of the solution is kept constant. 



8192 4096 Z048 1024 512 256 128 64 32 16 ^ 



Concentration 



FIG. 36. Showing that the depressing effect of salts with monovalent anion 

 on the swelling of gelatin chloride of pH 3.3 is similar to that on the relative 

 viscosity. All salts with monovalent anion depress the swelling of gelatin chlor- 

 ide to the same extent, the seeming deviation from this rule being due to variation 

 in the pH of the gelatin solution caused by buffer salts. 



What has been demonstrated for the effect of these salts on the 

 viscosity of gelatin solutions holds also for their effect on the 

 swelling of gelatin. The same volumetric method for measuring 

 the swelling effect was used which was described in the preceding 

 chapter. Figure 36 gives the relative depressing effect of NaCl, 

 NaH 2 P04, NaCNS, monosodium tartrate, monosodium citrate, 



