Why do electrodes need to be kept sperate in electrolysis experiments.

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Offline thedoc

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Shireen asked the Naked Scientists:
   Hi! When doing electrolysis experiments, why do the instructions say that the electrodes mustn't touch (assuming they are placed in the same beaker).
What do you think?
« Last Edit: 01/08/2016 10:23:01 by _system »


Offline evan_au

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I assume that by "electrolysis", you are doing experiments like passing electricity through salty water to produce hydrogen and oxygen, or through a copper sulphate solution to coat the electrode with a film of copper?

In these experiments, the electrodes are often metal, which has much higher conductivity than the liquid solution.

If the electrodes touch, all the current will flow directly from one electrode to the other electrode, without passing through the liquid.
The result: no electrolysis of the liquid, and a (potentially) damaged power supply. In extreme cases you could cause a fire.

It is best to arrange the electrodes to have a large area, and positioned close together without touching. A thin, porous material can be used as a spacer to keep the electrodes apart.