ELECTROSYNTHESIS. 303 



electrode, and the particles with positive electricity moving 

 towards the negative electrode. These particles, or ions, 

 are charged with definite amounts of electricity, all particles 

 of the same kind having the same charge. For our present 

 purpose we are not concerned whether the particles always 

 exist in the solution in the electrically charged condition, or 

 whether they merely assume that condition under the in- 

 fluence of the current : all that we need consider is that the 

 ions arrive charged at the electrodes and there lose their 

 charges. In a salt solution the metallic radical carries the 

 positive electricity, and the acid radical the negative elec- 

 tricity. Thus in a solution of common salt, Na CI, we 



+ 

 have the positive ion, or cation, Na, and the negative 



ion, or anion, CI. As long- as the ions retain their charges 

 they must be looked upon as being different in many re- 

 spects from the corresponding uncharged atoms or groups 

 of atoms. When, however, they are discharged at the 

 electrodes they regain their ordinary chemical character- 

 istics and enter into the appropriate reactions. If they are 

 capable of existing in the free state after discharge, they 

 will be liberated as such ; or they may react with each 

 other, with the water in which they are dissolved, with the 

 material of the electrode, etc. By suitable choice of con- 

 ditions we may favour any of these possible modes of 

 action at the expense of the others. 



Let us now consider the case of potassium acetate in- 

 vestigated by Kolbe. The formula we ascribe to this 



+ 

 compound is CH 3 *COOK, and it will yield the ions K and 



— + 



CH 3 *COO. The ion K on discharge at a platinum elec- 

 trode at once shows a characteristic property of potassium 

 by reacting with the water of the solution, with formation 

 of potassium hydroxide and liberation of hydrogen — 



2K-+2H 2 = 2KOH + H 2 . 



When the anion is discharged at the positive electrode, 

 also constructed of platinum in Kolbe's experiment, it can 

 react either with the water, or with itself, according to the 

 equations — 



