Sacrificial metals are specially selected metals used to prevent the corrosion of another metal by exhibiting higher reactivity.

More specifically, sacrificial metals play a crucial role in a technique known as cathodic protection. This method controls the corrosion of a metal surface by designating it as the cathode in an electrochemical cell. The sacrificial metal, which is more reactive, serves as the anode. Consequently, the sacrificial metal will corrode preferentially, thereby protecting the other metal from degradation.

For instance, zinc is commonly employed as a sacrificial metal to inhibit rusting in iron and steel. Zinc’s higher reactivity compared to iron ensures that it will corrode first. When zinc is attached to iron or steel, it acts as a protective barrier, preventing oxygen and water from reaching the underlying metal. This effectively halts the rusting process of the iron or steel.

This technique is widely utilized across various industries, including the marine sector for safeguarding ship hulls and the construction industry for protecting underground pipelines. It is a cost-effective and efficient strategy for extending the lifespan of structures and equipment exposed to corrosive environments.

The selection of a sacrificial metal is dependent on the metal that requires protection. The sacrificial metal must be more reactive than the protected metal according to the electrochemical series. For example, magnesium is often used to protect aluminum, while zinc is typically used to safeguard iron and steel.

In summary, sacrificial metals exemplify a practical application of the reactivity series in chemistry. They serve to protect valuable or significant metals from corrosion by being more reactive and, thus, corroding first.