Anode
Definition and meaning of Anode in chemistry.
An anode is the electrode at which oxidation occurs in an electrochemical cell. In a galvanic cell, the anode is the negative terminal; in an electrolytic cell, it is the positive terminal.
In more detail
In any electrochemical process, the anode is where oxidation takes place, electrons are released and flow through an external circuit to the cathode. The specific designation of the anode depends on the cell type: in a battery (galvanic cell), the anode spontaneously loses electrons, driving current through the external circuit; in an electrolytic cell, external voltage forces oxidation to occur at the anode. Understanding anodes is essential for designing and optimizing batteries, fuel cells, electroplating systems, and corrosion prevention strategies.
Key facts
| Field | Physical Chemistry |
|---|---|
| Process | Oxidation (electron loss) |
| In galvanic cells | Negative terminal |
| In electrolytic cells | Positive terminal |
In a simple zinc-copper galvanic cell, the zinc electrode serves as the anode, where zinc atoms lose electrons and dissolve into the solution as Zn²⁺ ions, while copper acts as the cathode where reduction occurs.
Frequently asked questions
How is an anode different from a cathode?
The anode is where oxidation occurs (electrons are released), while the cathode is where reduction occurs (electrons are gained). Together, they complete the electron flow in an electrochemical cell.
Is the anode always negative?
No. The anode is negative in galvanic cells but positive in electrolytic cells. The key defining feature is that oxidation occurs at the anode regardless of cell type.