How do ions move in an electrolytic cell?

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Discussion Overview

The discussion centers on the movement of ions, specifically OH- ions, within an electrolytic cell using pure water. Participants explore the mechanisms of ion migration and charge transfer, considering both physical movement and interactions with other ions and water molecules.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether OH- ions physically migrate from the anode to the cathode or if they transfer electrons/protons between H3O+ ions.
  • Another participant asserts that both physical migration and charge transfer occur, highlighting the high conductivity of H+ and OH- ions due to their unique interactions with water molecules.
  • A participant with an electronics background discusses the flow of ions in relation to applied potential energy, suggesting that ions can flow freely unlike atoms in solids.
  • Some participants clarify that stable ions exist in solution and do not require ionization from neutral atoms, challenging the notion that only neutral atoms can become ions.
  • There is a discussion about the stabilization of ions by water molecules, with references to solvation and the role of dipoles in maintaining ion stability.
  • A participant proposes a reaction during electrolysis involving the movement of protons and electrons, prompting further clarification on the nature of ionic bonds and solvation.

Areas of Agreement / Disagreement

Participants express differing views on the nature of ion stability in solution and the mechanisms of ion movement. There is no consensus on whether ions are stable solely due to their interactions with water or if they require additional context for stability.

Contextual Notes

Some assumptions about the nature of ions, their stability, and the specifics of charge transfer processes remain unresolved. The discussion also touches on the differences between behavior in liquids and solids, particularly at the microscopic level.

nuby
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Hello

I'm wondering if someone can explain how OH- ions physically move from the anode to the cathode within an electrolytic cell (w/ pure water) .

Do they physically migrate from one side to the other? Or do they just pass electrons/protons back and forth between other ions H3O+ to the other side?

Thanks
 
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Both.

H+ and OH- conductivity is much higher than that of other ions of smilar size and charge. That's because protons jump between water molecules free electron pairs:

Code: 
H-O-H[sup]+[/sup]  O-H          H-O   [sup]+[/sup]H-O-H
  |     |      ->      |      |
  H     H              H      H

Similar process works for OH-m aking charge transfer through the solution much faster.

Sorry about ASCII graphics, but it is 0:30 am here and I am spent.
 
nuby said:
Hello

I'm wondering if someone can explain how OH- ions physically move from the anode to the cathode within an electrolytic cell (w/ pure water) .

Do they physically migrate from one side to the other? Or do they just pass electrons/protons back and forth between other ions H3O+ to the other side?

Thanks

I'm not a chemistry fellow, but I am a electronics engineer tech fellow.
I'd say that with water and gasses...instead of JUST having free electrons flowing... You have atoms that are capable of flowing since they're not bonded together. As I'm sure you know that atoms naturally seek to be neutral. An Ion is a positively charged or negatively charged atom. This happens through losing a electron or gaining an electron. Now... if you put a potential energy source to the applied cell. You'll have electrons leaving atoms and joining with other atoms. Leaving atoms ionized. These ionized atoms unlike in copper atoms can flow since they're not stuck together so they will flow to whatever different potential. Positive ions will flow to negative potential, and Negative ions will flow to positive potential.
That's the difference between current through gasses and liquids vs current through solids like copper.
And the AMPS will be measured like this Q/T
Charge per second.

I hope this helps in anyway... since I'm not a chemist I don't know if I've answered your question or not.
 
Type_R said:
Iif you put a potential energy source to the applied cell. You'll have electrons leaving atoms and joining with other atoms. Leaving atoms ionized.

No. In general in the solution that is able to conduct electricity you don't have just atoms, that will get ionized. You already have ions, that are stable in this charged form.
 
Borek said:
No. In general in the solution that is able to conduct electricity you don't have just atoms, that will get ionized. You already have ions, that are stable in this charged form.

Stable in a charged form?

I've never heard of atoms being stable while being positive/negatively charged. Unless they're in an ionic bond in which they're balanced due to the positively charged ion bonded to the negatively charged ion. But as far as free ions I wouldn't know about that.

If you're right though i'd love to learn more about this.
 
Type_R said:
Stable in a charged form?

Yes. They are stabilized by water molecules dipoles. Look for solvation.
 
Borek said:
Yes. They are stabilized by water molecules dipoles. Look for solvation.

Ok that's what I suspected...They're being stabilized by essentially an ionic bond with different charges.

I thought you were saying they were stable completely by themselves.
 
Does this occur often during electrolysis:

H2O H2O + voltage => H3O+ OH-

Where a proton moves to the right toward the anode.
And electron moves left toward the cathode.
 
Last edited:
Type_R said:
Ok that's what I suspected...They're being stabilized by essentially an ionic bond with different charges.

I think I know what you mean, but this is not an ionic bond. Water molecules are dipoles, but they are not charged.

Besides, in the case of large, multiatomic ions, solvation plays very small role. You may treat them as stable by themselves.

This world is governed by its own laws. They don't contradict physics as you know it, but - especially on micro scale - they are in many aspects completely different from the solid state ones. Charge transfer between atoms/ions means chemical reaction, and to proceed these require that some conditions are meet.
 

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