# Why is the electrolyte in a cell necessary?

1. Oct 30, 2014

If electrons always flows from an area of high density to low density, why is it necessary for the ions in a cell to flow across the electrolyte as well. It seems that charge should be able to flow from the anode to the cathode without the need of these ions flowing as well. Why are these two processes mutually dependent on one another to create a steady voltage?

2. Nov 4, 2014

### Greg Bernhardt

Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

3. Nov 4, 2014

### Danger

If I understand your question correctly, it's because electrons can't "jump". ie: they need a conductive medium in which to "propagate" like billiard balls from one electrode to the other. Space in between would act as an insulator. (In the case of the somewhat misnamed "cathode ray" tube like in a TV, they are violently accelerated by an external voltage source rather than just seeking an electrical balance as in a battery.)
That's not a great explanation, I know, but for now it's the best that I can do with my limited scientific vocabulary.

4. Nov 4, 2014

### Staff: Mentor

Charges don't exist in isolation: in order to have a negative charge you have to start with a neutral charge and separate it into positive and negative. The positive ions exist to be re-combined with the electrons -- the attraction between them is what generates the voltage.

5. Nov 11, 2014

### Bandit127

Apologies if this is a bit basic, but I will put it another way.

Electrons don't flow in isolation. A charged capacitor is a good example of two different electron densities very close to each other but unable to flow. Thus the capacitor stores the electrons as a potential charge.

A spark plug is also worth thinking about here. Until the difference in potential between the contacts is sufficient no electrons will flow. (When it is sufficient, 10s of thousands of volts, a spark is created).

In both cases the resistance is too large for the electrons to flow at battery voltages.

Both the spark plug and the capacitor would allow the flow of electrons if we were to wire up a resistor between the contacts. The electrolyte does exactly that - creates a resistance that is sufficiently low enough for electrons to flow.

Last edited: Nov 11, 2014