Mercury spill on aluminum surfaces typically results in corrosion that is

• A. Slow and negligible
• B. Not possible at room temperature
• C. Easily cleaned with water
• D. Rapid and severe

Answer: (D)

Mercury’s interaction with aluminum hinges on how aluminum normally resists corrosion. Aluminum forms a thin, adherent oxide layer that passivates the surface and slows or stops reactions. Mercury, however, can disrupt that protective oxide and even form an amalgam with aluminum at the surface. This breaks down the passivation and allows mercury to penetrate and attack the underlying metal, creating rapid, localized corrosion and pits. The effect happens readily at room temperature because mercury is liquid and spreads easily, promoting intimate contact with the metal surface. Cleanup is not straightforward—mercury adheres strongly and can leave behind damaged areas, so damage can progress quickly even if the spill is small. For these reasons, corrosion from a mercury spill on aluminum is rapid and severe.