An experiment requires separating ethanol from a 250 mL solution that contains 30 % ethanol by volume. Simple distillation is used, and the first distillate is collected at 78 °C, which contains pure ethanol. If 60 mL of distillate is collected, what volume of ethanol was recovered, and what percentage of the ethanol present in the original solution has been recovered? Assume 100 % collection efficiency.
Answer
Recovered volume = 60 mL, which is 80 % of the original ethanol.
The correct answer is Recovered volume = 60 mL, which is 80 % of the original ethanol. — Thus 60 mL of ethanol is recovered, amounting to 80 % of the ethanol originally present.
Step-by-step solution
- Compute initial ethanol volume: 0.30 × 250 mL = 75 mL of ethanol in the mixture.
- Since the first distillate is pure ethanol, the volume of ethanol recovered = volume of distillate = 60 mL.
- Calculate percentage recovered: (60 mL ÷ 75 mL) × 100 % = 80 %.
- Thus 60 mL of ethanol is recovered, amounting to 80 % of the ethanol originally present.
Common mistake: Ignoring the initial ethanol volume or mixing up volumes and percentages
Concept tested: Distillation
Published · How this solution was prepared and checked
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