# If you run an electrolytic cell long enough, does the conductivity decrease?

I've never seen this discussed so I wanted to ask here. Consider the electrolysis of water with inert electrodes and electrolytes that won't be oxidized or reduced, such as sodium sulfate. Since the migration of electrolytes in an electrolytic cell is responsible for the electrical current, does the gradual sequestering of electrolytes at the electrodes decrease the electrolyte concentration in the middle (between the electrodes), and cause a decrease in conductivity?

A couple thoughts occur to me:

1. the $\ce{H+}$ and $\ce{OH-}$ will diffuse from the electrodes into the cell water. As the $\ce{H+}$ and $\ce{OH-}$ diffuse back into bulk they could carry the electrolytes with them.

2. the battery could be disconnected momentarily to mix the electrolyte solution.

• If anything, gradual buildup of $\ce H^+$ and $\ce{OH}^{-}$ in their corresponding areas should increase the conductivity. – Ivan Neretin Feb 1 '16 at 5:47

1. the $\ce{H+}$ and $\ce{OH-}$ will diffuse from the electrodes into the cell water. As the $\ce{H+}$ and $\ce{OH-}$ diffuse back into bulk they could carry the electrolytes with them.