Understanding Iron Corrosion Process

This document outlines the chemical reactions involved in the formation of rust on iron. It explains the interaction between iron and moist air, leading to corrosion, and details the microscopic processes at play.

Step 1

One of the most common forms of corrosion is the transformation of iron into rust. To understand this phenomenon, we delve into the microscopic level at the interface between iron and moist air. Oxygen molecules dissolved in water attack iron atoms and strip away two electrons, forming iron(II) ions (Fe²⁺).

Step 2

Simultaneously, the movement of electrons, oxygen, and water results in the formation of hydroxyl ions. This marks an initial stage, but the oxidation process continues further.

Step 3

Oxygen further reacts with the iron(II) ions (Fe²⁺), extracting an additional electron and transforming them into iron(III) ions (Fe³⁺). This ongoing reaction continues to generate new hydroxyl ions. Ultimately, iron(III) ions combine with hydroxyl ions to form a precipitate.

Step 4

This results in the bright orange rust that spreads across the surface. This rust will gradually penetrate deeper, attacking the still intact iron atoms, albeit more slowly and less vigorously, leading to the formation of darker rust.