Examkin

Question

Difficulty: MediumAluminium: Extraction, Amphoteric Properties, Alloys, and Compounds

Concentrated trioxonitrate(V) acid can be safely stored and transported in containers constructed from aluminium metal. Which of the following chemical phenomena accounts for this behavior?

  1. Formation of an impervious, protective surface oxide filmAnswer
  2. B
    High standard reduction potential preventing acid attack
  3. C
    Precipitation of an insoluble trioxonitrate(V) salt lining the container
  4. D
    Neutralization of the acid by the basic nature of aluminium metal

Answer

Formation of an impervious, protective surface oxide film
Concentrated trioxonitrate(V) acid is a powerful oxidizing agent that renders aluminium passive by forming a thin, dense, and non-porous oxide coating over its surface. This continuous protective barrier prevents the acid from contacting the bulk metal underneath.

Step-by-Step Solution

1
Examine the chemical action of concentrated trioxonitrate(V) acid on aluminium metal.
Concentrated trioxonitrate(V) acid acts as a powerful oxidizing agent.
Upon contact with aluminium, it immediately oxidizes the metal surface.
2
Determine the physical consequence of the surface oxidation.
A thin, tough, and impermeable oxide layer covers the surface of the metal.
This process, termed passivity, shields the underlying bulk aluminium from undergoing further chemical attack by the acid.

Key Concept

Aluminium oxide passivity
Rate this question

Topics

Aluminium: Extraction, Amphoteric Properties, Alloys, and Compounds

More questions from this topic