# Can the ions of dissolved salts be physically separated with a strong enough external electric field?

Say you had a arbitrary amount of sodium chloride dissolved in water. Could an external electric field (e.g. the electrically charged plates in Millikan's oil drop experiment) physically pull apart the dissolved ions in the water if it was strong enough? What forces would it need to overcome?

If it is possible, how powerful would the electric field have to be? What would be the outcome if the $$\ce{Na+}$$ and $$\ce{Cl-}$$ ions were then physically separated into two different containers?

• I think you went too far with the follow up question. Less the struck out part the question should be okay. – A.K. Oct 5 '18 at 19:27
• Rather than close this question I think it could easily be edited. – A.K. Oct 5 '18 at 19:27

Could an external electric field (e.g. the electrically charged plates in Millikan's oil drop experiment) physically pull apart the dissolved ions in the water if it was strong enough?

What forces would it need to overcome?

Yes, this is the principle behind electrophoresis and electric double layer supercapacitors where charge is separated by an electrostatic field shown below.

Diagram of Double Layer Capacitor charging and Discharging

What would be the outcome if the $$\ce{Na+}$$ and $$\ce{Cl-}$$ ions were then physically separated into two different containers?

Assuming you could so this without any interaction with the container, you would have 2 Leyden Jars that were opposite in charged and storing a lot of energy.

• Is water usually not the electrolyte in these cases? – Zhe Oct 5 '18 at 20:28
• That just won't happen. You can't put more than a couple of volts on the electrodes without electrolyzing the water. Yes you can polarize the electrodes but that will create a double layer. So a layer of $\ce{Cl^-}$ ions will attract a layer of $\ce{Na+}$ ions. Thus you can't separate $\ce{Cl^-}$ ions in one half of a cell and $\ce{Na+}$ ions in the other half. – MaxW Oct 5 '18 at 21:13