What is the role of the anode in an electrochemical cell?

In an electrochemical cell, the anode is specifically defined as the site where oxidation occurs. This is a critical concept in electrochemistry, as it helps to understand the flow of electrons during the electrochemical reactions that take place.

During oxidation, a substance loses one or more electrons. At the anode, this process involves the transfer of electrons from the oxidized species to the external circuit, which drives the overall reaction of the electrochemical cell. As the anode is where oxidation happens, it also serves as the source of electrons that travel through the circuit to the cathode, where reduction (the gain of electrons) takes place.

The anode is typically designated as the positive electrode in galvanic cells (spontaneous reactions) and the negative electrode in electrolytic cells (non-spontaneous reactions). The distinction can lead to confusion, but the essential role of the anode remains the same: it is fundamentally involved in the oxidation process, regardless of its charge state in a given type of cell. This central role in oxidation confirms that the correct response highlights its position as the positive electrode in spontaneous electrochemical reactions.