Electroneutrality
Potassium and Chloride Ions Diffusing in Solution
Initially, all the positively charged potassium ions are distributed on the left half of the solution and all the negatively charged chloride ions are on the right. Press the "restart" button and watch how rapidly the ions come together to neutralize each others' electric field. This is refered to as electroneutrality. The electric force is so strong that, paradoxically, it moves the charges so as to cancel itself out. Thus any conducting volume more than a few nm on a side will contain nearly equal amounts of positive and negative charge.For the purposes of this demonstration you can turn off the electric interaction (this is not possible in reality) so that the ions no longer respond to each others' electric field. Turn this interaction off and restart the simulation. Then turn the interaction on again to see how strongly the electric interaction affects diffusion.
The electric potential display underneath the ions shows the voltage differences generated in the solution by the electric charges. Note how the voltages differences are reduced as the positive and negative ions intermingle. For the purpose of this simulation, only horizontal electrical fields and voltage differences are considered, and vertical differences are ignored.