Science (086) — AI-generated practice question

The flaw in the student's reasoning is ignoring the protective oxide layer that forms on aluminium's surface.

Although aluminium is highly reactive, when exposed to air it reacts with oxygen to form a thin, tough layer of aluminium oxide (Al₂O₃):

$$4\text{Al} + 3\text{O}_2 \rightarrow 2\text{Al}_2\text{O}_3$$

This oxide layer is stable and strongly adherent. It prevents further reaction of the underlying aluminium with air or moisture, thereby protecting it from corrosion. Because of this self-protective behaviour, aluminium does not corrode rapidly and is safe and durable for making cooking utensils.

Source: Chapter 3, Section 3.2.1

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• The key concept examiners look for is the protective oxide layer — name it, explain it forms immediately on exposure to air, and state it prevents further corrosion.
• Writing the balanced equation for aluminium oxide formation earns a mark and shows chemical understanding.
• Avoid just saying "aluminium doesn't corrode" — you must explain why (the oxide coat acts as a barrier). That reasoning is the heart of the answer.
• The word "amphoteric" is not required here; stay focused on the corrosion-resistance aspect.