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Galvanic cell electrodes

In a galvanic cell, the oxidation half-reaction occurs at the anode (see Figure 1). Since electrons are deposited on this electrode, it is the negative electrode. The reduction half-reaction occurs at the cathode, which loses electrons and is therefore the positive electrode.

Galvanic cell electrodes. Two almost full beakers are placed beside each other. One beaker is full of zinc sulfate and it contains a plate of zinc, which is the anode. The other beaker is full of copper sulfate and it contains a piece of copper, which is the cathode. A wire is connecting both metal plates, which allows the transfer of electrons from the anode to the cathode. This wire also has a voltmeter that is measuring the electric potential. There is a tube that contains salt connecting both solutions from the two beakers. In the first beaker, the zinc ions are moving from the metal plate towards the solution and, at the same time, two electrons are being released. In the other beaker, copper ions are moving towards the metal plate and two electrons are also transferred to the anode.

Figure 1: Galvanic cell electrodes: electrons are lost from silver at the anode (oxidation) gained by copper at the cathode (reduction reaction).

The electrons are transferred from silver to copper via the external circuit.