Question

Absolute ethanol cannot be obtained by simple fractional distillation because:

• A. it is pure
• B. it forms hydrogen bonding with water
• C. boiling point of ethanol and water are very near
• D. it forms a constant boiling azeotropic mixture with water

Answer 1

The correct option is D it forms a constant boiling azeotropic mixture with water

During fractional distillation, ethanol forms an azeotropic mixture with $95.6\%$ ethanol and $4.4\%$ water (percentage by weight).

This mixture has a boiling point of ${78.2}^{o}C$ which cannot be further purified by distillation and hence absolute ethanol cannot be obtained.

Option D is correct.