Electrochemical cells, electrolysis, and corrosion

Electrochemistry connects redox reactions and electricity. In a galvanic (voltaic) cell, a spontaneous redox reaction produces an electric current: the oxidation and the reduction happen at two separate electrodes, so electrons must travel through an outside wire to get from one to the other. Oxidation happens at the anode and reduction at the cathode, and a salt bridge or porous barrier lets ions move to keep the charges balanced. Batteries are galvanic cells, from alkaline batteries to the lithium-ion batteries in phones, which can be recharged by pushing current through them in the opposite direction. Electrolysis does the reverse: an outside power source forces a redox reaction to happen that would not happen on its own. Electrolysis is used to split water into hydrogen and oxygen, to produce aluminum and chlorine, and to electroplate a thin layer of metal, such as silver or chromium, onto an object. Corrosion is an unwanted redox reaction: iron rusts when oxygen oxidizes it in the presence of water. Paint, oil, galvanizing (coating iron with zinc), or attaching a more easily oxidized metal as a sacrificial anode helps protect iron from rusting.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report