Solutions and Colligative PropertieshardMCQ SINGLE⭐ Must-Do

During the fractional distillation of fermented aqueous sugar, the concentration of ethanol reaches Solutions and Colligative Properties Chemistry Question

Question

During the fractional distillation of fermented aqueous sugar, the concentration of ethanol reaches a rigid limit of approximately $96\%$ by volume. Why is it impossible to obtain $100\%$ absolute alcohol by continuing this simple distillation?

Answer: C

💡 Solution & Explanation

Ethanol and water show a large positive deviation, leading to a minimum boiling azeotrope at ~96%. At this point, the vapour produced has the identical mole fraction as the liquid phase, rendering fractional distillation completely ineffective.

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