When using ethanol in the setup, what arrangement is best and why?

• A. Leave the apparatus open to air to ensure ventilation.
• B. Cover the apparatus with a lid, because ethanol is volatile.
• C. Place the apparatus in direct sunlight to aid evaporation.
• D. Use a larger beaker to dilute the ethanol.

Answer: (B)

Ethanol is highly volatile and flammable, so the safest approach in a setup is to minimize evaporation and vapour release. Covering the apparatus with a lid helps trap the liquid and reduce the amount that evaporates into the air, lowering the risks of inhalation exposure and fire. Leaving it open to air would let more ethanol escape as vapour, direct sunlight would heat the liquid and boost evaporation, and simply using a larger beaker doesn’t reduce vapour release or fire risk.