Subject: Electrolysis of aqueous KI

This is a question concerning the electrolysis of aqueous potassium iodide (transparent light yellow), when the solution is electrolyzed with direct current 12 volt in a U tube (two electrodes), hydrogen gas is produced and the solution is getting clearer at Cathode side, some dark brown liquid (precipitate?), evidently denser is produced at Anode side constantly. After 20 minutes, there is a sharp boundary at the bottom of the U tube between the nearly clear solution from Cathode and the brown precipitate from Anode.

Iodide ions, I-, and iodate ions, IO3- are colorless. I would like to know why is there a sharp color boundary noted near the bottom of the U-tube? What is the equation for the reaction involved? And what may be the approximate H+ ion concentration at Cathode?

Thank you

Re: Electrolysis of aqueous KI