Question

The technique used for purification of steam volatile water immiscible substance is:

• A. Fractional distillation
• B. Fractional distillation under reduced pressure
• C. Distillation
• D. Steam distillation

Answer 1

The Correct Option is D

To address the question, the optimal purification method for a steam-volatile, water-immiscible substance must be identified.

Let's examine each option:

1. Fractional distillation: Suitable for separating miscible liquids based on boiling point differences. Inappropriate for water-immiscible substances reliant on steam volatility for separation.
2. Fractional distillation under reduced pressure: Lowers boiling points for heat-sensitive compounds by reducing pressure. Does not specifically address steam-volatile, water-immiscible substances.
3. Distillation: A general separation technique based on vaporization at boiling points. Does not exploit steam volatility, rendering it unsuitable.
4. Steam distillation: Specifically purifies steam-volatile, water-immiscible substances. Involves passing steam through the mixture, vaporizing volatile compounds at reduced temperatures due to steam's presence, a critical benefit for these substances.

Consequently, Steam distillation is the correct choice. It excels at purifying steam-volatile, water-immiscible substances by efficiently separating volatile components without requiring complete boiling or miscibility in water.

Thus, steam distillation leverages the substance's volatility with steam, facilitating its collection in a cooled receiver.