Aluminium is suitable for making alloys for aircraft construction because it

Step 1: Analyze the question We need the property of aluminium that makes its alloys good for building aircraft. Aircraft materials must be light (low density), strong, and able to resist corrosion from air and moisture.

Step 2: Explain the concept Aluminium is a light metal with a density of about 2.7 g/cm³, much lower than iron (about 7.9 g/cm³). It also forms a thin, tough, unreactive layer of aluminium oxide (Al₂O₃) on its surface when exposed to air. This layer protects the metal underneath from further corrosion. Alloys such as duralumin (Al with Cu, Mg, Mn) add strength while keeping the metal light.

Step 3: Evaluate each option

• A. Hard and brittle: Wrong. Brittle materials crack easily, which is dangerous in aircraft. Aluminium is ductile and malleable.
• B. Light and very resistant to corrosion: Correct. Both properties suit aircraft construction.
• C. High density and a non-conductor of electricity: Wrong. Aluminium has low density and is a good conductor of electricity.
• D. Amphoteric and allotropic: Aluminium is amphoteric (its oxide reacts with both acids and bases), but this is not why it is used in aircraft. It is also not allotropic.

Step 4: Answer The correct option is B. is light and very resistant to corrosion.

Tip: For "why is metal X used for Y" questions, match the property to the use. Aircraft need lightness and corrosion resistance. Electric cables need conductivity and ductility. Cooking pots need good heat conduction and non-toxicity. Also remember that "brittle" is almost never the right answer for a construction material.