Skill 27.2 Demonstrate an understanding of electrolysis reactions

Electrolytic cells use electricity to force nonspontaneous redox reactions to occur while electrochemical cells generate electricity by permitting spontaneous redox reactions to occur. The two types of cells have some components in common. 

Both systems contain two electrodes. An electrode is a piece of conducting metal that is used to make contact with a nonmetallic material. One electrode is an anode. An oxidation reaction occurs at the anode, so electrons are removed from a substance there. The other electrode is a cathode. A reduction reaction occurs at the cathode, so electrons are added to a substance there. 

Electrons flow from anode to cathode outside either device. 

Electrolysis is a chemical process driven by a battery or another source of electromotive force. This source pulls electrons out of the chemical process at the anode and forces electrons in the cathode. The result is a negatively charged cathode and a positively charged anode. 

Electrolysis of pure water forms O2 bubbles at the anode by the oxidation halfreaction  

---