Chapter 20, Problem 80A

Interpretation Introduction

Interpretation:

Explain if the coating of copper would protect iron from rusting or not.

Concept introduction:

A metal coating can protect another metal from corrosion if it is of a lower reduction potential than the target metal.

Answer to Problem 80A

Copper would not be able to protect iron from corrosion if the coating becomes broken or cracked because copper has a higher reduction potential than iron.

Explanation of Solution

The metal to be plated on iron must have a lower reduction potential than iron it self so that it can act as a sacrificial anode during rusting and protect iron but in the case of copper it has higher reduction potential than iron so it will not be able to protect the metal once the coating breaks.

Conclusion

A cracked or broken copper coating cannot protect iron due to its higher reduction potential.