Question
Explain the term “corrosion” with an example. Write a chemical equation to show the process of corrosion of iron.
✓
Answer
Corrosion is the process in which metals are eaten up gradually by the action of air, moisture or a chemical (such as an acid) on their surface. Rusting of iron metal is the most common form of corrosion. During the corrosion of iron, iron metal is oxidised by the oxygen of air in the presence of water (moisture) to form hydrated iron oxide called rust.
$4\text{Fe}\ \ +\ \ 3\text{O}_2\ \ \ +\ \ 2\text{xH}_2\text{O}\ \xrightarrow{\ \ \ \ \ \ \ \ \ \ \ \ \ \ }\ 2\text{Fe}_2\text{O}_3\cdot\text{xH}_2\text{O}\\ ^\text{Iron}\ \ \ \ \ \ \ \ \ ^\text{Oxygen}\ \ \ \ \ \ \ \ \ ^\text{Water}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ^\text{Hydrated iron oxide(Rust)}$
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