Primary and Secondary Results of ' Electrolyzatiofi. 261 



mode of decomposition are applicable here as were made in 

 relation to the chlorides when in solution (766.). 



770. Hydro-fluoric Acid and Fluorides. — Solution of hydro- 

 fluoric acid did not appear to be decomposed under the in- 

 fluence of the electric current : it was the water which gave 

 way apparently. The fused fluorides were electrolyzed (417.); 

 but having during these actions ohinmed fluorine in the sepa- 

 rate state, I think it better to refer to a future series of these 

 Researches, in which I purpose giving a fuller account of the 

 results than would be consistent with propriety here. 



771. Hydro-cyanic acid in solution conducts very badly. 

 The definite proportion of hydrogen (equal to that from 

 water) was set free at the cathode, whilst at the anode a small 

 quantity of oxygen was evolved and apparently a solution of 

 cyanogen formed. The action altogether corresponded with 

 that on a dilute muriatic or hydriodic acid. When the hydro- 

 cyanic acid was made a better conductor by sulphuric acid, 

 the same results occurred. 



Cyanides. — With a solution of the cyanide of potassium, 

 the result was precisely the same as with a chloride or iodide. 

 No oxygen was evolved at the positive electrode, but a brown 

 solution formed there. For the reasons given when speaking 

 of the chlorides (766.), and because a fused cyanide of potas- 

 sium evolves cyanogen at the positive electrode*, I incline to 

 believe that the cyanide in solution is directly decomposed. 



772. Ferro-cyanic acid and the Jerro-cyanides, as also sid- 

 pho-cyanic acid and the sulpho-cyanides, presented results cor- 

 responding with those just described (771.). 



773. Acetic Acid — Glacial acetic acid, when fused (405.), 

 is not decomposed by, nor does it conduct, electricity. On 

 adding a little water to it, still there were no signs of action ; 

 on adding more water, it acted slowly and about as water 

 alone would do. Dilute sulphuric acid was added to it in 

 order to make it a better conductor; then the definite propor- 

 tion of hydrogen was evolved at the cathode, and a mixture 

 of oxygen in very deficient quantity, with carbonic acid, and 

 a little carbonic oxide, at the anode. Hence it appears that 

 acetic acid is not electrolyzable, but that a portion of it is de- 

 composed by the oxygen evolved at the anode, producing se- 

 condary results, varying with the strength of the acid, the in- 

 tensity of the current, and other circumstances. 



774. Acetates.— One of these has been referred to already, 



* It is a very remarkable thing to see carbon and nitrogen in this case 

 determined powerfully towards the positive surface of the voltaic battery j 

 but it is perfectly in harmony with the theory of electro-chemical decom- 

 position which I have advanced. 



