In which of the following situations would you use a laboratory fume hood?

• A. When preparing a solution by dissolving table salt in water
• B. When working with volatile or toxic chemicals that produce hazardous vapors
• C. When heating water in a beaker to boiling using a hot plate
• D. When measuring the mass of a solid sample using an analytical balance

Answer: (B)

Verified step by step guidance

1. Understand the purpose of a laboratory fume hood: it is designed to protect users from inhaling hazardous vapors, gases, or dust by ventilating and containing them.
2. Identify situations that involve volatile or toxic chemicals which can release harmful vapors into the air, requiring the use of a fume hood for safety.
3. Evaluate each given scenario: dissolving table salt in water does not produce hazardous vapors, so a fume hood is not necessary.
4. Heating water in a beaker produces steam (water vapor), which is generally not toxic or hazardous, so a fume hood is not required.
5. Measuring the mass of a solid sample on an analytical balance does not involve vapors or hazardous emissions, so a fume hood is not needed.