Question

Which one of the following mixtures can be separated by steam distillation technique?

• A. n-Hexane + n-Heptane
• B. CHCl₃ + Aniline
• C. Aniline + H₂O
• D. Glucose + NaCl

Hint:

Classic examples of compounds purified by steam distillation include aniline, nitrobenzene, o-nitrophenol (to separate from p-nitrophenol), and essential oils from plants. The key characteristics to look for are immiscibility with water and steam volatility.

Answer 1

The Correct Option is C

Step 1: Principle of Steam Distillation: Steam distillation is used to separate substances which are: 1. Steam volatile (have appreciable vapor pressure at steam temp). 2. Immiscible with water.
Step 2: Analyze Options: (A) n-Hexane + n-Heptane: Both liquid hydrocarbons, miscible, different boiling points. Separated by Fractional Distillation. (B) \( \text{CHCl}_3 \) + Aniline: Miscible organic liquids with different B.P. Separated by Distillation. (C) Aniline + \( \text{H}_2\text{O} \): Aniline is an organic liquid that is immiscible with water but is steam volatile. Hence, it can be purified/separated from a mixture (usually reaction mixture) using steam distillation. (D) Glucose + NaCl: Solid mixture. Separated by crystallization or solvent extraction (solubility difference). Conclusion: Aniline and water mixture is the classic example for steam distillation.