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Reviewed CSCA Chemistry question · Hard

A student accidentally breaks a mercury thermometer in the laboratory. Which of the following is the most appropriate immediate action?

  1. Use a vacuum cleaner to suck up the mercury droplets.
  2. Cover the spill with sulfur powder and then carefully collect the mercury.
  3. Pour water over the spill to wash the mercury down the drain.
  4. Leave the spill and notify the teacher at the end of the lab period.
Show the answer and explanation

Correct answer

B. Cover the spill with sulfur powder and then carefully collect the mercury.

Principle or equation

Mercury is toxic and volatile. It should be contained and treated with sulfur to form mercury(II) sulfide, reducing vapor release, then collected and disposed of properly.

Why this answer is correct

Sulfur reacts with mercury to form a non-volatile solid, making cleanup safer. Vacuuming can aerosolize mercury droplets; water does not dissolve mercury; delaying cleanup increases exposure risk.

Example

Sprinkle sulfur powder over the mercury droplets, then use a brush and dustpan to collect the amalgam into a labeled waste container.

This published item includes a stored explanation and passed the platform’s publication workflow. It is independent preparation material, not a claim of an official or recalled examination question.

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