A student accidentally breaks a mercury thermometer in the laboratory. Which of the following is the most appropriate first step in cleaning up the spill?
Show the answer and explanation
Correct answer
B. Sprinkle sulfur powder over the mercury and then collect the amalgam.
Principle or equation
Mercury is toxic and volatile. Sulfur reacts with mercury to form mercury(II) sulfide, a less hazardous solid, reducing vapor exposure. Vacuuming or sweeping spreads droplets; washing down the sink contaminates water.
Why this answer is correct
Mercury spills require careful handling. Sulfur powder is used to immobilize mercury by forming a solid amalgam that can be safely collected. Vacuuming increases vaporization and spread. Water does not react with mercury and would contaminate drains. Sweeping spreads the mercury into smaller droplets.
Example
A broken thermometer releases a few grams of mercury. Sprinkling sulfur powder over the spill forms a gray-black solid (mercury sulfide) that can be swept up with a brush and disposed of as hazardous waste.
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