To prevent corrosion of iron, we must consider the electrode potentials of the metal to be used for coating. A metal that has a higher (less negative) reduction potential will be more easily reduced and less likely to corrode.
The metal with the more negative reduction potential will act as a sacrificial anode, corroding in place of the iron.
1. For metal X:
The reduction potential of is , which is very negative. This means that metal X is more easily oxidized and will corrode easily, making it unsuitable for coating the surface of iron.
2. For metal Y:
The reduction potential of is , which is less negative than metal X. This means metal Y is more stable and less likely to corrode than metal X.
3. For iron (Fe):
The reduction potential of is , which is less negative than X but more negative than Y. Iron itself will corrode over time if left unprotected.
Conclusion:
Metal Y is the better choice for coating the surface of iron to prevent corrosion because it has a less negative reduction potential compared to iron and X. As a result, it will be more stable and less likely to corrode, offering better protection to the iron surface.