Chemistry
Electrochemistry & batteries — quick study summary
Electrochemistry studies redox reactions that produce or use electricity. A galvanic cell (battery) uses a spontaneous redox reaction to push electrons through a wire — chemical energy → electrical. An electrolytic cell uses electricity to force a non-spontaneous reaction (e.g. electrolysis of water → H₂ + O₂). Standard electrode potentials predict which metals oxidise more easily; combining them gives the overall cell voltage.
Key points
- Oxidation at the anode; reduction at the cathode (AN OX, RED CAT)
- Galvanic cell: spontaneous redox → electricity (battery)
- Electrolytic cell: electricity → forces non-spontaneous reaction (electroplating, refining)
- E°cell = E°cathode − E°anode; positive → spontaneous
- Salt bridge maintains charge balance between half-cells
Practice quiz
Click each question to reveal the answer.
1. In a galvanic cell, which electrode is the site of oxidation?
- Anode
- Cathode
- Salt bridge
- Electrolyte
Answer: Anode
Mnemonic AN OX, RED CAT: oxidation always happens at the anode, reduction at the cathode.
2. What is electrolysis?
Answer: Using electricity to force a non-spontaneous redox reaction
Pass current through a melt or solution and you can split compounds — e.g. water into H₂ + O₂ or molten NaCl into Na + Cl₂.
3. What is the role of the salt bridge in a galvanic cell?
Answer: Maintains charge balance by allowing ions to flow between the half-cells
Without the salt bridge, charge would build up in each half-cell and the reaction would stop.
Last reviewed: May 2026