You seem to have got it covered Roger. I might just add that the oxygen reaction at the anode is unlikely to proceed at low voltages, as silver is oxidised at a much lower potential.
Ivan. ----- Original Message ----- From: <[email protected]> To: <[email protected]> Sent: Saturday, 24 March 2001 06:08 Subject: Re: CS>Solubility of silver in water. > In a message dated 3/23/01 11:16:13 AM EST, [email protected] writes: > > << Subj: Re: CS>Solubility of silver in water. > Date: 3/23/01 11:16:13 AM EST > From: [email protected] (Del or Elmay Crow) > Reply-to: [email protected] > To: [email protected] > > Sorry, but you guys are confusing me. The thing you are dealing with is a > change of energy levels.The silver is still silver. There is supposedly no > metal exchanged between the annode and cathode. All you could expect is > that the water is changed to accomodate this. Bubbles of hydrogen at one > side, oxegen at the other plus the water electron-cloud structure change to > possibly up to 105degrees. None of us can measure this stuff, let alone > imagine it!!! >> > > Del: I think what you have to keep in mind is when ~27 volts are applied > across silver electrodes in pure water, certain oxidation/reduction reactions > are possible. > > Let's look at the anode where oxidation takes place. At the voltage stated, > these are the reactions that MAY take place, > > (1) Ag -------> [Ag+] + 1e > (2) 1/2O2(g) + 2[H+] -----> H2O + 1e > (3) 2[OH-] -----> H2O + 1/2O2 + 1e > > > And for the cathode, the following reactions MAY take place, > > (4) [Ag+] + 1e -------> Ag > (5) [H+] + 1e --------> 1/2H2(g) > (6) H2O + 1e --------> 1/2O2(g) + 2[H+] > > Now, the way I remember how to proceed, and it has been a very long time > since I did these calculations, is to examine the standard electrode > potential for each reaction. The reaction that has the smallest absolute > electrode potential will proceed under STANDARD conditions, that is. In this > case, however, water is essentially the electrolyte (at least in the > beginning of CS electrolysis) so we can use the standard electrode potential > directly to determine which of the "water reactions" will proceed, and since > water is in abundance, that reaction will set the maximum potential at that > electrode. Now, here's where silver enters the picture: If silver can be > oxidized at the anode at the maximum electrode potential (dictated by one of > the water reactions), silver ions will be produced. Similarly at the cathode, > if silver ions can be reduced at the maximum electrode potential (dictated by > one of the water reactions) then metallic silver will be produced (from the > silver ions generated at the anode). Perhaps, Ivan (or anyone else versed in > electrochemistry) can fill in the blanks with regard to which of these water > reactions will prevail at the anode and cathode, and/or whether or not I made > any boo boos. Roger --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.237 / Virus Database: 115 - Release Date: 08/03/2001 -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <[email protected]>
