Which statement about handling extraction solvents is true?

• A. Adequate ventilation should always be used when dealing with extraction solvents.
• B. Weigh approximately 500 ml of the extract into a bowl and evaporate the solvent as quickly as possible to avoid fumigation.
• C. The ash weight is subtracted from the remaining aggregate to calculate binder content.
• D. Pycnometers should be calibrated each day of use.

Answer: (A)

Handling extraction solvents safely hinges on controlling the vapors they emit. Adequate ventilation is essential because many solvents are volatile and potentially toxic; providing proper airflow—whether through local exhaust, a fume hood, or a well‑ventilated area—keeps vapor concentrations well below dangerous levels and reduces fire or explosion risk. In practice, never work with solvents in confined spaces without ventilation, regularly check that exhaust systems are functioning, and combine ventilation with other safety steps like keeping containers closed when not in use and having spill containment ready. The other statements don’t fit the safety context: rushing evaporation increases vapor exposure and fire risk; binder-content calculations are unrelated to solvent handling; and calibrating a pycnometer has no bearing on solvent safety.