Resistance of a solution between two electrodes

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Discussion Overview

The discussion revolves around calculating the resistance of a solution between two point electrodes in a complex cylindrical beaker. Participants explore theoretical and practical considerations related to the geometry of the setup and the behavior of ions in solution.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant notes the standard resistance formula R=ρL/A applies only to the fluid directly between the electrodes, not accounting for the entire volume of fluid in the beaker.
  • Another participant suggests that the current will likely take the shortest path between the electrodes, implying that the resistance of the fluid directly between them is the main factor to consider.
  • A third participant mentions that an electric field will be established between the electrodes, causing ions to drift towards one electrode or the other, indicating the influence of ion species on resistance.
  • One participant questions whether the inquiry is theoretical or practical, highlighting the complexity of calculating resistance due to geometry and suggesting the use of conductometric experiments to determine the cell constant.

Areas of Agreement / Disagreement

Participants express differing views on the factors influencing resistance, with some focusing on the direct path of current and others considering the broader implications of geometry and ion behavior. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants acknowledge the complexity of the geometry involved and the potential need for experimental determination of parameters like the cell constant, which may affect calculations.

jagnala
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I have a complex cylindrical shaped beaker with two point electrodes and wanted to calculated the resistance between them?

I know that:
R=ρL/A

But this equation only takes into account the fluid directly between the two electrode and not the remaining fluid in the breaker.

Thanks
 
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Hi Jagnala
welcome to PF :smile:

I would suspect that the current is going to take the shortest (most direct) path between the 2 electrodes and therefore the resistance of the fluid between those points is the primary consideration.

lets see whay others have to say

cheers
Dave
 
Well, there will ne an electrical field set up between the electrodesd and the ions will drift to one electrode or the other depending on the species.

Here is one take on the subject.
http://www.chem.ox.ac.uk/teaching/Physics%20for%20CHemists/Magnetism/Resistance.html

Scroll down to the heading Conductance of Ions in Solution
 
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Is this a theoretical question, or are you looking for a practical way of finding the result? Because of the geometry these things are difficult to calculate. That's why we start precise conductometric experiments by experimentally determining the cell constant (which is what you are looking for).
 

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