What process occurs at the cathode in an electrochemical cell?

In an electrochemical cell, the cathode is defined as the electrode where reduction occurs. This process involves the gain of electrons by a species in the solution, which results in a decrease in the oxidation state of that species.

When a redox reaction takes place in an electrochemical cell, oxidation occurs at the anode, leading to the release of electrons that flow towards the cathode. At the cathode, these electrons are accepted by the ions or molecules present, facilitating their reduction. For example, if copper(II) ions are reduced, they gain two electrons to form solid copper metal.

Understanding this process is crucial, as it reflects the fundamental electrochemical principles where the flow of electrons generates electrical energy. Thus, the cathode's role in reduction is a central aspect of how electrochemical cells function, contrasting the processes that occur at the anode and further defining the overall chemistry of the cell.