Precise Volume Measurement in Chemistry

Steps:

• Identify the requirement: apparatus must deliver exactly 27 cm³ (27 mL) of liquid with high accuracy.
• Recall functions: evaluate each option based on its design for volume delivery.
• Compare precision: burette offers variable, fine graduations; others are fixed or approximate.
• Select best fit: choose tool calibrated for exact, adjustable volumes like 27 mL.

Why A is correct:

• A burette is a graduated tube with fine scale (0.1 mL intervals) for precise delivery of any volume up to 50 mL, per standard lab definitions.

Why the others are wrong:

• B. a condenser: Designed for cooling vapors during distillation, not volume measurement.
• C. a measuring cylinder: Provides approximate volumes with coarser graduations (±1 mL accuracy), unsuitable for exact amounts.
• D. a volumetric pipette: Delivers only fixed, pre-calibrated volumes (e.g., 10 or 25 mL), not arbitrary 27 mL.

Final answer: A