MDCAT Chemistry MCQ #5420

Aluminum containers can be used to store and transport concentrated nitric acid. What specific mechanism makes the aluminum metal 'passive' in this highly corrosive acid?

MDCAT Chemistry MCQ #5420

  1. Question 1

    Q1. Aluminum containers can be used to store and transport concentrated nitric acid. What specific mechanism makes the aluminum metal 'passive' in this highly corrosive acid?

    • A) Formation of a protective oxide layer
    • B) Evolution of nitrogen dioxide gas bubbles
    • C) Precipitation of aluminum nitrate crystals
    • D) Reduction of aluminum to its hydride form

    Answer: Formation of a protective oxide layer

    Explanation: Concentrated HNO3 forms a thin, non-porous layer of Al2O3 on the surface of aluminum, preventing further reaction; HCl would dissolve the metal.