Which metal is more reactive, aluminium or iron?

• A. Aluminium
• B. Iron
• C. Copper
• D. Zinc

Answer: (A)

The main idea here is metal reactivity: how easily a metal loses electrons to form positive ions. In the reactivity series, metals higher up are more reactive and will push out or replace metals that are less reactive. Aluminium sits above iron, so it tends to lose electrons more readily. This means aluminium is more reactive than iron.

A practical clue is the tendency of a more reactive metal to reduce compounds of a less reactive metal. For example, aluminium can reduce iron oxide to iron in a thermite-type reaction, which shows its stronger reducing power. The apparent calmness of aluminium in air comes from a thin oxide layer that forms quickly and protects it, making it seem less reactive under ordinary conditions. But that layer doesn’t change the underlying fact: aluminium is more easily oxidized than iron, so it is the more reactive metal.