The Zn acts as sacrificial or cathodic protection to prevent rusting of iron because: (a) \(E_{\mathrm{OP}}^{\circ}\) of \(\mathrm{Zn}E_{\text {OP }}^{\circ}\) of \(\mathrm{Fe}\) (c) \(E_{\text {OP }}^{\circ}\) of \(\mathrm{Zn}=E_{\mathrm{OP}}^{\circ}\) of \(\mathrm{Fe}\) (d) \(\mathrm{Zn}\) is cheaper than iron

In the realm of electrochemistry, standard electrode potentials, represented as E^o, are crucial in understanding the behavior of metals in reactions. These potentials are quantitative measures of a metal's tendency to gain or lose electrons, known as reduction or oxidation, respectively.

A more negative E^o value indicates a greater eagerness to relinquish electrons and undergo corrosion. In the context of the exercise, evaluating the E^o values for zinc (Zn) and iron (Fe) helps determine which metal will act as the sacrificial anode in cathodic protection. The metal with the lower (more negative) standard electrode potential will preferentially corrode, protecting the other metal from rusting. Thus, understanding these potentials is essential for designing systems that prevent corrosion through electrochemical means.

The fight against metal corrosion is a pivotal aspect of maintaining the integrity of structures and devices. Corrosion prevention can be achieved through various methods, with cathodic protection being one of the most effective.

Employing a sacrificial anode, typically a metal like zinc, provides cathodic protection by allowing the anode to corrode instead of the metal it is safeguarding, which serves as the cathode. This method relies on the principle that certain metals corrode more easily than others. By selecting a sacrificial metal with a lower standard electrode potential, the protected metal remains unscathed, showing the practical application of the theoretical principles of electrochemistry in preserving infrastructure.

An electrochemical cell is a device that generates electrical energy from chemical reactions or facilitates chemical reactions through the introduction of electrical energy. It consists of electrodes submerged in electrolytes, which are substances containing free ions that allow the substance to be electrically conductive.

When considering cathodic protection, the system functions as a type of electrochemical cell where the sacrificial anode and the metal to be protected form the two electrodes. The sacrificial anode's lifespan and the protected metal's corrosion rate are both determined by the cell's potential difference. By applying the principles of electrochemical cells, engineers can design systems to prevent the corrosion of critical metal components, ensuring longevity and performance.