VELOCITY OF REACTIONS 



Sulphate of copper is immediately precipitated by 

 potassium hydroxide as a light blue gelatinous de- 

 posit of hydroxide of copper. When we add sugar 

 solution, or solution of sodium tartrate, this deposit 

 is dissolved into a dark blue liquid. This liquid no 

 longer shows the characteristics of solutions which 

 contain simple ionic copper. Therefore copper 

 ions cannot be present. Those present are com- 

 pound ions containing both copper and the organic 

 substance. 



Similar processes are, as we know,, common 

 in living cells. But living cells can even form 

 new ions from non-ionic substances. When 

 oxalic acid is formed from sugar or protein 

 matter, new ions of this strong acid come into 

 existence. Many other cases of the production 

 of ions from non-electrolytes in living cells could 

 be mentioned. When reactions between ions 

 take place in protoplasm, they are not carried out 

 in a watery liquid medium, but in a colloidal 

 medium. It is a question, however, whether the 

 Reaction Velocity is the same as in water. Ex- 

 perimental work of the last years does not leave 

 any doubt that a colloidal medium diminishes the 

 velocity of chemical reactions as well as the diffu- 

 sion of dissolved substances. Thus it is certain 

 that colloids of firmer consistence, such as solid 

 gels, must retard the course of chemical reactions, 

 even of ions. In spite of this, ionic reactions are 

 completed in an immeasurably short time, and 

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