Electrochemical reduction electrons traveling from electrode

Charge flows through the cell as soon as the wires of the electrodes touch each other, with electrons travelling from the more negative to the more positive electrode. It is these electrons which allow the reduction reaction to proceed at the right-hand side of the cell, where they are consumed as part of the electrode reaction. Since the electrons from the left fuel the reaction at the right, we see that the extent of electrochemical reaction must be the same at both sides of the cell. We say that these reactions are complementary. 

The cathode is defined as the electrode at which reduction occurs, i.e., where electrons are consumed, regardless of whether the electrochemical cell is an electrolytic or voltaic cell. In both electrolytic and voltaic cells, the electrons flow through the wire from the anode, where electrons are produced, to the cathode, where electrons are consumed. In an electrolytic cell, the dc source forces the electrons to travel nonspontaneously through the wire. Thus, the electrons flow from the positive electrode (the anode) to the negative electrode (the cathode). However, in a voltaic cell, the electrons flow spontaneously, away from the negative electrode (the anode) and toward the positive electrode (the cathode). 

The energy produced in a chemical reaction may also be extracted electrically. The device needed is called an electrochemical cell, which is a reaction vessel equipped with two electrodes. Oxidation (the loss of electrons) takes place at one electrode (the anode), and the electrons lost from the reactant are transferred to the electrode. They then travel through an external circuit, which might contain an electric motor, and re-enter the reaction vessel at the other electrode (the cathode), where they bring about reduction (the gain in electrons). In a primary cell, the reactants are sealed in at time of manufacture and the production of electricity continues until the... 

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