The constituent common to duralumin and alnico is

Analysis

To solve this question, we need to identify the chemical composition of two specific industrial alloys: duralumin and alnico. We are looking for the common element present in both.

Concept Explanation

• Alloys are mixtures of two or more metals (or a metal and a non-metal) designed to improve the properties of the base metal, such as strength, corrosion resistance, or magnetism.
• Duralumin is a lightweight, high-strength alloy primarily used in the aircraft industry. Its composition is roughly 95% Aluminium (Al), 4% Copper (Cu), 0.5% Manganese (Mn), and 0.5% Magnesium (Mg).
• Alnico is a powerful magnetic alloy. Its name is derived from its main components: Aluminium (Al), Nickel (Ni), and Cobalt (Co).

Step-by-Step Solution

1. Break down Duralumin: The primary constituent is Aluminium (Al). It also contains small amounts of Copper, Manganese, and Magnesium.
2. Break down Alnico: The name itself gives away the components: Aluminium, Nickel, and Cobalt.
3. Compare the components: • Duralumin: Al, Cu, Mn, Mg • Alnico: Al, Ni, Co
4. Identify the common element: Comparing the two lists, the only element that appears in both is Aluminium (Al).

Conclusion

My analysis confirms this, as Aluminium is the base metal for both alloys.

Exam Tip: When dealing with alloy questions in JAMB, always look at the name of the alloy. Often, the name is a portmanteau (a blend) of the chemical symbols or names of the metals involved (e.g., Alnico = Aluminium + Nickel + Cobalt). This is a great way to save time during the exam!