It's well known that if you place 2 electrodes connected to a battery in salt water, Positive ions will get attracted to the negative electrode, and negative ions to the positive electrode.

But what if in respect to salt water's potential both electrodes are at a (let's say 9008V and 9000V potential.) won't the positive ions get repelled by both electrodes and the negative ions attracted to both electrodes ?

EDIT #1 : The first awnser said that only potential difference matters but wouldn't positive charges going into positive charges get repelled (coulomb's law)

You may say it's because the other one has even more positive charges, but then this will mean it get's repelled to the other positive electrode and dosen't mean attracted to lower potential electrode. And why wouldn't a positive ion just get repelled by both (coloumb's law) and stay in a corner of the container.

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    $\begingroup$ I think you might be confused about what a voltage is. Volts do not inherently mean a positive charge. The voltage would be across both electrodes, each electrode would not have its own voltage. $\endgroup$ – CuriousOne Oct 31 '19 at 16:09
  • $\begingroup$ Each electrode will have it's own potential relative to salt water $\endgroup$ – mohamed azaiez Oct 31 '19 at 16:37

Remember that in the case of potential, only the potential DIFFERENCE has any true physical meaning. You can set the zero potential to be anywhere and all other potentials will be in reference to that point. In other words, the zero potential is arbitrary.

Assigning an arbitrary 9000V to your lowest potential will not stop negative ions drifting to the positive $\Delta V$ and vice versa for positive ions.

  • $\begingroup$ i'am confused about something why dosen't the individual charges of the ions matter here ? like if they are positive they would like to go away from the other positive terminal because like charges repel. I used to know this but now i feel like i am forgetting something important . $\endgroup$ – mohamed azaiez Oct 31 '19 at 1:15
  • $\begingroup$ Positive charges go in the direction of potential drop. Why do you think 9008-9000 potential drop would push a charge less than 8-0 potential drop. A current in an electric circuit travels in the direction of decreasing potential. If you assign a point in the circuit as zero potential, every point upstream from that point is at positive potential. The current still flows between those positive potential points in the direction of decreasing potential. $\endgroup$ – Bill Watts Oct 31 '19 at 2:59
  • $\begingroup$ I think i got it. Positive ions will get repelled by positive charges in both electrodes .This will get some positive ions stuck in the corners of the container of salt water until the positive ions on the corner balance out the electric field and they are forced to go into more positive ions. $\endgroup$ – mohamed azaiez Oct 31 '19 at 8:26
  • $\begingroup$ I think you are confusing positive potential with positive charge. Just because the potential is positive at a point in a circuit, that does not mean there are positive charges there to repel anything. $\endgroup$ – Bill Watts Oct 31 '19 at 16:27
  • $\begingroup$ Ok i am going to make an other question to clarify $\endgroup$ – mohamed azaiez Oct 31 '19 at 16:46

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