1921] Electrosynthesis in Organic Chemistry 351 



WEEKLY EVENING MEETING, 



Friday, April 22, 1921. 



Sir James Reid, Bart., G.C.V.O. K.O.B. M.D. LL.D. F.R.C.P., 

 Manager and Vice-President, in the Chair. 



Sir James Walker, D.Sc. LL.D. F.R.S., Professor of 

 Chemistry, University of Edinburgh. 



Electrosynthesis in Organic Chemistry. 



[Abstract.] 



The decomposition of water into oxygen and hydrogen by means of 

 the electric current was effected by Nicholson and Carlisle in 1800, 

 and affords the first example of electrolysis. Davy applied the 

 electrolytic method to the decomposition of many compounds, and 

 finally succeeded in isolating the alkali metals, potassium and 

 sodium, by the electrolysis of fused potash and soda. 



Faraday, his successor in the chair of the Royal Institution, laid 

 the foundations of our theoretical knowledge of the subject. He 

 studied in detail the nature and proportions of the products obtained 

 by electrolysis, reduced the manifold experimental data to a simple 

 system, and invented the nomenclature employed at the present day. 

 The process of electrolysis in aqueous solution is conceived by him 

 as follows : When two conducting plates connected with the opposite 

 poles of a battery are immersed in a conducting solution, negative 

 electricity travels towards the positive plate (positive electrode, anode), 

 and positive electricity travels towards the negative plate (negative 

 electrode, cathode). The electricity does not travel alone, but in 

 association with a material carrier or ion, the anion or negatively 

 charged ion moving towards the anode, whilst the cation or posi- 

 tively charged ion moves towards the cathode. Chemically equiva- 

 lent quantities of the ions bear equal charges of electricity. When 

 the ions reach the electrodes they are there discharged, and may then 

 act (1) upon each other, (2) upon the water in which they are dis- 

 solved, or (3) upon the material of the electrodes. Thus, if we 

 electrolyse sulphuric acid H 2 S0 4 , which yields the ions 2H + and 

 S0 4 ~ ~, we have at the negative electrode an action which may be 

 represented by the equation 



2 H = H 2 (1) 



