Why is rusting said to be one of the most expensive chemical reactions?

Answer 1

Rust is why most cars expire. Same can be said for ships, boats and most infrastructure.

Reinforced concrete is concrete armored often with steel and/or iron rebars and is a very common building material in most kinds of infrastructure. If the steel or iron rebars in the concrete begins rusting the concrete will crack as the corrosion swells the iron/steel and therefore creates a crack that propagates and exposes more iron/steel to the elements.

If a large part of the worlds automobiles, ships, boats and infrastructure are destroyed, in one way or another, by rusting, it is hard to think of a chemical reaction that can match it in cost.

Answer 2

Rusting is considered costly because it leads to the deterioration and structural weakness of metallic objects and structures, requiring frequent maintenance or replacement. Additionally, it can impact the overall functionality and lifespan of the affected materials, resulting in substantial repair or replacement expenses. Moreover, the economic impact of rusting extends beyond direct costs to include environmental damage and safety hazards.