What can be used to clean mercury?

• A. 10% nitric acid with 90% distilled water
• B. 70% isopropyl alcohol
• C. Household ammonia
• D. Water only

Answer: (A)

Cleaning mercury spills effectively hinges on turning the liquid metal into a form that can be collected and disposed of safely. A diluted nitric acid solution does this by oxidizing elemental mercury to mercuric ions, forming mercuric nitrate which dissolves in water. Using a mixture of 10% nitric acid with 90% distilled water keeps the reaction controlled and the mercury in a soluble form for cleanup. The other options don’t provide this oxidation step: water alone won’t convert mercury to a soluble form, isopropyl alcohol won’t oxidize mercury, and household ammonia can form unwanted mercury complexes and fumes rather than reliably enabling safe cleanup.