Detailed Discussion of Diagram of Voltaic Cell

Electrochemical cells that create electrical current from spontaneous reactions are called voltaic cells or galvanic cells.

In the voltaic cell in the next figure, the following occurs:

A solid strip of Zn is placed into a Zn2+ solution to form a half-cell.

A solid strip of Cu is placed into a Cu2+ solution to form a second half-cell.

The two half-cells are connected by attaching a wire from the Zn, through a lightbulb or other electrical device, to the copper.

The salt bridge completes the circuit—it allows the flow of ions between the two half-cells.

The natural tendency of Zn to be oxidized and Cu2+ to be reduced results in the flow of electrons through the wire.

The flowing electrons constitute an electrical current that lights the bulb.