Electrolysis is a process in which a chemical change, especially decomposition, is brought about by passing an electric current through a solution of electrolytes so that the electrolyte's ions move toward the negative and positive electrodes and react with them.
If negative ions move toward the anode, they lose electrons and become neutral, resulting in an oxidation reaction. This also happens if atoms of the anode lose electrons and go into the electrolyte solution as positive ions. If positive ions move toward the cathode and gain electrons, becoming neutral, a reduction reaction takes place. Electrolysis is used for many purposes, including the extraction of metals from ores, the cleaning of archaeological artifacts, and the coating of materials with thin layers of metal (electroplating).
When a direct current is passed through a liquid which contains ions (an electrolyte), chemical changes occur at the two electrodes; usually a separation of oxygen from hydrogen or other substances it is chemically bonded with. In our case the process of splitting water into hydrogen and oxygen.