Aluminium's Suitability for Aircraft

Steps:

• Identify requirements: low density for weight reduction and corrosion resistance for durability.
• Check aluminium's density: 2.7 g/cm³, lower than steel (7.8 g/cm³) or iron (7.9 g/cm³).
• Check corrosion resistance: aluminium forms a passive Al₂O₃ oxide layer that protects against oxidation.
• Confirm both properties match aircraft needs, selecting option A.

Why A is correct:

• Aluminium's low density reduces aircraft weight, improving fuel efficiency, while its natural oxide layer (from 4Al + 3O₂ → 2Al₂O₃) provides inherent corrosion resistance without additional treatments.

Why the others are wrong:

• B: Aluminium also resists corrosion via its oxide layer, so both properties apply.
• C: Aluminium has low density (2.7 g/cm³), so both properties apply.
• D: Aluminium exhibits both low density and corrosion resistance.

Final answer: A