Before turning on the heat for a microscale distillation, which of the following steps should be completed to ensure a safe and effective procedure?

• A. Check that all glassware is properly assembled and connections are secure.
• B. Seal the distillation apparatus completely to prevent vapor escape.
• C. Fill the receiving flask to the top with solvent.
• D. Add boiling chips after the liquid begins to boil.

Answer: (A)

Verified step by step guidance

1. Understand the purpose of preparing the distillation apparatus before heating: ensuring safety and preventing accidents such as glassware breakage or vapor leaks.
2. Recognize that properly assembling all glassware and securing connections prevents leaks of hot vapors and maintains the integrity of the apparatus during distillation.
3. Know that sealing the apparatus completely is important, but some setups require a vent or open system to avoid pressure buildup; thus, sealing must be done appropriately, not necessarily completely airtight.
4. Avoid filling the receiving flask to the top with solvent, as this can cause overflow or contamination; it should be partially filled to safely collect distillate.
5. Add boiling chips before heating begins to promote smooth boiling and prevent bumping; adding them after boiling starts is ineffective and unsafe.