Question

Ordinary aluminium strips are not attacked by water because of the presence of a layer of ______ on the surface of aluminium.

Answer 1

Ordinary aluminium strips are not attacked by water because of the presence of a layer of aluminium oxide on the surface of aluminium.

Explanation:

Aluminium is a highly reactive metal that instantly reacts with oxygen in the air to form a thin, tough, and impervious layer of aluminium oxide. This stable oxide film adheres tightly to the metal surface, acting as a protective barrier that prevents water or oxygen from penetrating deeper into the underlying metal. Because of this self-passivating property, ordinary aluminium strips remain unattacked by water under normal conditions. The protective layer is chemically represented as Al₂O₃.