Question

Absolute alcohol can be obtained from rectified spirit by:

• A. Fractional distillation
• B. Azeotropic distillation
• C. Vacuum distillation
• D. Steam distillation

Answer 1

The correct option is B

Azeotropic distillation

Explanation of the correct option:

Option B is correct:

1. 100% pure ethanol (${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$) is known as absolute alcohol which is obtained from rectified spirit.
2. Azeotropic distillation is defined as the separation of all the azeotropic mixture by the process of distillation. Absolute ethanol can be obtained from rectified spirit by azeotropic distillation.

Explanation of the incorrect options:

Options A, C, and D:

1. The separation of a mixture into its constituent elements, or fractions, is known as fractional distillation.
2. Vacuum distillation is the process of distilling at decreased pressure to purify substances that are difficult to distil at ambient pressures or simply to save time and energy.
3. Steam distillation is a separation method that involves distilling water with other volatile and non-volatile ingredients.

Hence, option B is correct.
Absolute alcohol can be obtained from rectified spirit by azeotropic distillation.