100 THEORY OF COLLOIDAL BEHAVIOR 



. Our valency rule demands that the relative depressing 



M 



ft ft ft fe f 9 : 9 



Concentration. 



FIG. 33. The depressing effect of different salts with monovalent anion 

 (NaCl, NaH 2 PO 4 , NaCNS, NaH tartrate, and NaH 2 citrate) on the relative 

 viscosity of 0.8 per cent solution of gelatin chloride of pH 3.0. The effects of 

 NaCl and NaHzPCh are identical since the pH is not altered by the addition of 

 these salts. The depression in the values for the relative viscosity is greater in 

 the case of Na acetate than in the case of NaCl for the reason that the Na acetate 

 raises the pH of the gelatin chloride solution. 



effect of these salts (with the exception of Na 2 SO 4 ) should be 



