Anode

Diagram of a zinc anode in a galvanic cell. Note how electrons move out of the cell, and the conventional current moves into it in the opposite direction.

An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ACID, for "anode current into device".[1] The direction of conventional current (the flow of positive charges) in a circuit is opposite to the direction of electron flow, so (negatively charged) electrons flow from the anode of a galvanic cell, into an outside or external circuit connected to the cell. For example, the end of a household battery marked with a "+" is the cathode (while discharging).

In both a galvanic cell and an electrolytic cell, the anode is the electrode at which the oxidation reaction occurs. In a galvanic cell the anode is the wire or plate having excess negative charge as a result of the oxidation reaction. In an electrolytic cell, the anode is the wire or plate upon which excess positive charge is imposed.[2] As a result of this, anions will tend to move towards the anode where they will undergo oxidation.

Historically, the anode of a galvanic cell was also known as the zincode because it was usually composed of zinc.[3][4]: pg. 209, 214 

  1. ^ Denker, John (2004). "How to Define Anode and Cathode". av8n.com. Archived from the original on 28 March 2006.
  2. ^ Pauling, Linus; Pauling, Peter (1975). Chemistry. San Francisco: W. H. Freeman. ISBN 978-0716701767. OCLC 1307272.
  3. ^ "Zincode definition and meaning | Collins English Dictionary". collinsdictionary.com. Retrieved 11 June 2021.
  4. ^ Ross, S (1961). "Faraday Consults the Scholars: The Origins of the Terms of Electrochemistry". Notes and Records of the Royal Society of London. 16 (2): 187–220. doi:10.1098/rsnr.1961.0038. S2CID 145600326.