Basic Electrolysis

[HairBear]

Good morning ladies! I see you have already started a good discussion this very beautiful Sunday morning. Farrah's Grotthuss mechanism, it seams to fit rather well. Although, what is the assumed voltage potential? Will this reaction occur through all levels of voltage or is there a threshold where the proton or electron is overcome by attraction and repulsion forces caused by the higher voltages which may cause ionization by collision?

[witsend]

Good morning ladies! I see you have already started a good discussion this very beautiful Sunday morning. Farrah's Grotthuss mechanism, it seams to fit rather well. Although, what is the assumed voltage potential? Will this reaction occur through all levels of voltage or is there a threshold where the proton or electron is overcome by attraction and repulsion forces caused by the higher voltages which may cause ionization by collision?

LOL HairBear. I'm not sure of that Grotthuss mechanism - will need to look it up and I've spent the most of my afternoon trying to get my head around some basic electrolysis from Google. Added to which I'm deferring a whole lot of diagrams that I promised because it's excessively boring. And I'm still secretely waging war on electrons collecting anywhere at all at those pesky anodes and cathodes. So. I'm delighted it's a beautiful morning at your end of the world. Here it's progressing into night and my understanding is getting correspondingly dark. LOL

What I need is a book on 'CHEMISTRY FOR KINDERGARDEN'. Is there such a thing?

[HairBear]

Two points I would like to add. Molecular polarization by voltage and the bond angle of the molecule changing from 109 to 104 degrees also caused from voltage. How do these properties affect the process?

[Farrah Day]

HB

Although, what is the assumed voltage potential? Will this reaction occur through all levels of voltage or is there a threshold where the proton or electron is overcome by attraction and repulsion forces caused by the higher voltages which may cause ionization by collision?

Just need the minimum voltage to initiate electrolysis. Once we have the ions H+ and OH- (through whatever means) that proton can't exist by itself for any length of time and so combines with a nearby water molecule to form H3O+.

Rosemary

The Grotthus Mechanism, if you're unsure, suggests that the proton moves through the aqueous medium similarly to how we perceive an electron to move through a solid conductor, effectively by hopping from water molecule to water molecule. But this mechanism applies only to the H+ ion (the proton), not to a hydrogen atom.

It is a neutral hydrogen atom left at the anode after the OH- gives up it's electron and the O mates up with another oxygen atom, not H+, so the Grotthus Mechanism would not come into the equation.

So, what's occurring...?

Farrah

[Mookie]

I have been a reader of this forum for many years and have followed this particular thread with much interest since it was started. The original question truly goes to the heart of the matter. The recent reference to Prof Ehrenhaft has prompted me to join this forum, if only briefly, to add what I can to this thread. I was hoping the conversation would eventually lead to the subject of "magnetic current" which I believe to be very much relevant to the answer. I have studied Prof Ehrenhaft's work for several years, and have successfully duplicated many of his experiments. Let me be direct and to the point. Magnetic current has a profound accelerating effect on the rate of electrolysis. Conservatively in the area 10 to 15 times. I have built several simple "accelerators" to demonstrate that fact. Do I understand why, or what it is that causes this effect? I do not. Is it the electrons that are affected by the magnetic field or the charge-carrying ions themselves that are being influenced? I only have propositional explanations and theoretical answers. Magnetic current is quite real, and has a dramatic accelerating effect on the rate of electrolysis. Does this provide a lead toward answering your original question ? Perhaps it does. I do not know. But it is the road on which I travel.

[Harvey]

HB



Just need the minimum voltage to initiate electrolysis. Once we have the ions H+ and OH- (through whatever means) that proton can't exist by itself for any length of time and so combines with a nearby water molecule to form H3O+.

Rosemary

The Grotthus Mechanism, if you're unsure, suggests that the proton moves through the aqueous medium similarly to how we perceive an electron to move through a solid conductor, effectively by hopping from water molecule to water molecule. But this mechanism applies only to the H+ ion (the proton), not to a hydrogen atom.

It is a neutral hydrogen atom left at the anode after the OH- gives up it's electron and the O mates up with another oxygen atom, not H+, so the Grotthus Mechanism would not come into the equation.

So, what's occurring...?

Farrah

See the section "How does it work" on this webpage:
Electrolysis


What seems to be missing from the discussion thus far is Dissolved Gases:

http://www.microseeps.com/pdf/dgaanion.pdf

[witsend]

Conversely, the OH- travels through the liquid medium (through one process or another) to the anode. Here it gives up it’s electron to become OH, so we have an aqueous oxygen atom and an aqueous hydrogen atom. The oxygen atom combines with another oxygen atom to form an oxygen molecule and evolves as gas.

So here’s the thing… what happens to the aqueous hydrogen atom that remains at the anode?

Golly Farrah. I've struggled here. The OH- is at the anode. The proton would be classed as a cation - therefore postive. Surely it would need to get to the cathode to gain a charge? The only way that I see it could do this would be to form another (aqueous) molecule and then do that Gottheus dance step number back to the cathode. The only molecules available are H2O. That - in turn would give you another H3O+? (is that hydroneum?) And is that then the source of the two way flow of currents proposed by the alternating flow of anions and cations?

EDITED. Just thought of an alternative solution. The proton takes an electron from the anode and discharges as hydrogen?

Come on Farrah. You'll need to tell us the answer.

Also, please advise me because I've read it somewhere and am still not sure. Is the required applied energy for electrolysis from a DC or AC source? I NOW can't find an answer to this ANYWHERE.

edited

[Farrah Day]

Hi Mookie

Is it the electrons that are affected by the magnetic field or the charge-carrying ions themselves that are being influenced?

Any charged particle can be infuenced by a magnetic field, so both electrons and ions can be influenced. So yes to both. Remember an ion is only an ion because of an excess or shortage of electrons.

Incidentally Mookie, I'm currently working on a proof of concept device, which I call a closed-loop electrolyser that incorporates neos.

Rosemary

If the OH- gives up a single electron to the anode, we are not left here with an oxygen atom and a proton, which I think is where the confusion lies. No, OH is then effectively a neutral molecule - one oxygen atom and one hydrogen atom (not a proton here).

So when the oxygen atom buggers off, we're left with a hydrogen atom.

Harvey, I'll take a look at that later... got to go out today.

Regards, Farrah.

[witsend]

If the OH- gives up a single electron to the anode, we are not left here with an oxygen atom and a proton, which I think is where the confusion lies. No, OH is then effectively a neutral molecule - one oxygen atom and one hydrogen atom (not a proton here).

So when the oxygen atom buggers off, we're left with a hydrogen atom.

Hi Farrah. Is that the answer? But then I've missed something. You mentioned that the oxygen forms a molecule - O2? The hydrogen is discharged? But we started with 2 x hydrogen and 1 x oxygen. I'm still missing a hydrogen atom somewhere.

[witsend]

If the OH- gives up a single electron to the anode, we are not left here with an oxygen atom and a proton, which I think is where the confusion lies. No, OH is then effectively a neutral molecule - one oxygen atom and one hydrogen atom (not a proton here).

So when the oxygen atom buggers off, we're left with a hydrogen atom.
Regards, Farrah.

Sorry. I get it. I think. The OH is actually discharged? Is that a stable molecule? Then the remaining proton gets back its electron? The only confusion then is the two oxygens which you referenced earlier - and the stability of OH? My guess is that it would need another hydrogen? So then the remaining hydrogen bonds with OH? NEAT. We're back to water. LOL



I might add - that was a fun learning curve. My guess is you're a teacher. Thanks for the puzzle Farrah.

[CatLady]

From Harveys electrolysis link above we find the following quote;

Meanwhile, the positive anode has caused the negatively charged hydroxide ion (OH-) to travel across the container to the anode. When it gets to the anode, the anode removes the extra electron that the hydroxide stole from the hydrogen atom earlier, and the hydroxide ion then recombines with three other hydroxide molecules to form 1 molecule of oxygen and 2 molecules of water:

4 OH- _> O2 + 2 H2O + 4e-

So it takes 4 hydroxide ions at the anode to make 1 oxygen gas molecule and 2 water molecules. The way I see it that equation says the anode gets 4 free electrons. Shouldn't the equation end with 1e-?

[Mookie]

Farrah


I believe I know your intent with your closed-loop electrolyser with neos.

Electrons are inherently lazy, but the extent to which they will go to in seeking an opposite charge is quite remarkable. Electrons in an electrolyte will travel in circles, and around corners in order to complete their mission. Although deadly, they are also the friendliest little bastards when tamed.
The electrical process obviously continues in the ionized electrolyte,
otherwise it would not be affected by a magnetic field. In a properly aligned magnetic field, electrons and, or, charged ions can be lined up behind eachother to "draft" within that field, quite similarly to racing cars pulling in behind each to reduce friction.

Should you not achieve your desired result with neos do not stop there.

.

[Farrah Day]

Ok, I didn't intend to be messing with your brains, I was simply trying to get you thinking about this.

Rosemary

You got it.

Harvey and Catlady you found it too. But not many people ever talk about this anode reaction do they. Even the diagram from the link Harvey posted indicated that there would be a lone Hydrogen atom at the anode.

Anyway yep, we actually need four OH- ions to react together at the anode. All four ions each give up their electron (4e) to the anode, so we have left 4 x OH. Two oxygen atoms combine to form an oxygen molecule and are evolved as gas, while the remaining two OH molecules combine with the two leftover hydrogen atoms to form two new water molecules.

At least this is the standard explanation...
....exactly why the reaction takes place like this and so nicely balances, I haven't a clue. It does though rather beg the question what would happen if only two or three OH- ions reached the anode?

Regards, Farrah.

[witsend]

Rosemary

You got it.

LOL. That was quite steep learning curve there Farrah - but all is NOT yet WELL. Here's why.

Water ionises into H+ and OH- ions. The very unstable H+ ion bonds with the nearest available water molecule or cluster, forming an hydronium ion H3O+, and the proton gradually makes its way to the cathode via the Grotthus Mechanism.

Why does the proton - positively charged - move to the CATHODE? Surely it moves to the anode?

Conversely, the OH- travels through the liquid medium (through one process or another) to the anode.

And here it is again? Have I got it wrong? Do postives move to positive cathode and negatives to negative anode? Hopelessly confused here Farah. Please enlighten me.

Then. Regarding the applied current. I see that Sucahyo says that one can use alternating or DC to initiate electrolysis? Is that right?

And then with reference to this,

Incidentally Mookie, I'm currently working on a proof of concept device, which I call a closed-loop electrolyser that incorporates neos.

This is really intriguing. If current is induced in one direction and then reversed, would that automatically reverse the process? I've sort of got an idea where one could apply dc from two alternate battery supply sources, first in one direction and then in the other. That way one could effectively recharge the one battery when discharging the other. My interest would be if it would vary that electrolytic mix each time? Do you see what I'm saying? Otherwise I'll try and do a circuit sketch. But it would need the one battery to be acidic - such as lead acid and the other to be a standard alkaline mix.

May help that proposed 'closed' system? Certainly it would get the balance in the delivery of current in the first instance.

[Harvey]

Cathodes are negative

Anodes are positive

An E field exists between the two which polarizes the electrolytic, meaning that the molecules turn and align with the field and move toward the opposite polarity pole where possible under pressure from the electric force.


The thing that intrigued me the most in this discussion is the valence bonding of H2 and O2. The stable ground state of Oxygen is Triplet Oxygen which is paramagnetic, but there is also a form of O2 that is less stable known as singlet oxygen which is diamagnetic.

It is understood that moving electrical charges produce magnetic fields. So there can be no doubt that magnetism plays at least a minor role in the electrolysis process, and in the case of Ehrenhaft's work, a major role.

I would like to see another thread that discusses advanced electrolysis of pure water with zero minerals.

I would also like to see some mention of what pH really is and how it relates to this process and how it was used to prove the chemical reactions involved.