Role of over voltage in the electrolysis of brine solution
Answers
No Chlorine did not form. The reason is that in solution you have two species which are competing at the electrode Cl- and your water molecule. We simply have to inspect the Standard reduction potential table to see that Cl2 will not form. 2H2O (l) -----> O2 (g) + 4H+ (aq) + 4e ; E0 = -1.23 V
and 2 Cl- (aq) ------> Cl2(g) + 2e E0 = -1.36 V
The reaction with the lower voltage will prevail and so oxygen will form rather than chlorine.
If you were to replace the sodium chloride with sodium Iodide you will see a different result ( I2 will form).
I have not gone into the exact concentrations which will mean using the Nernst equation, but the result will be the same. Hope this helps.
due to over voltage reaction having lower oxidation potential will takes place
as e°(oxidation) cl- < e°(oxidation) oh- (h2o)
hence
cl- ------> cl2+ 2e-
