Question

The steam volatile compounds among the following are:

• A. (A) and (B) Only
• B. (A),(B) and (C) Only
• C. (B) and (D) Only
• D. (A) and (C) Only

Hint:

Steam volatile compounds are generally low-boiling compounds that can vaporize and mix with steam at low temperatures.

Answer 1

The Correct Option is A

To solve this problem, we need to understand the relationship between steam volatility, intermolecular forces (especially hydrogen bonding), and molecular structure.

1. Understanding Steam Volatility:
Steam volatile compounds can be distilled using steam distillation, meaning they vaporize readily in the presence of steam. This is favored by lower boiling points and weaker intermolecular forces.

2. The Role of Hydrogen Bonding:
Intramolecular hydrogen bonds (within a molecule) increase volatility because they reduce the molecule's ability to form strong intermolecular interactions. Intermolecular hydrogen bonds (between molecules) decrease volatility by increasing the strength of the interactions between molecules.

3. Identifying Key Factors:
The key factor determining steam volatility in this context is the presence of intramolecular hydrogen bonds. Molecules with these bonds are more volatile due to reduced intermolecular attraction.

4. Conclusion:
Molecules with intramolecular hydrogen bonds are more likely to be steam volatile.

Final Answer:
Molecules with intramolecular hydrogen bonds are more likely to be steam volatile are A and B

Answer 2

Step 1: Understand the concept of steam volatility.
Steam distillation is used to separate or purify organic compounds that are volatile in steam and immiscible with water. Compounds that can undergo steam distillation are those which:
- Are immiscible with water.
- Have sufficient vapor pressure at the boiling point of water (below 373 K).

Step 2: Analyze the given compounds.
(A) o-Nitrophenol — Due to intramolecular hydrogen bonding, it is less polar and more volatile; hence, it is steam volatile.
(B) o-Nitroaniline — Also has intramolecular hydrogen bonding, making it less associated and more volatile; hence, it is steam volatile.
(C) p-Aminophenol — It has intermolecular hydrogen bonding, which increases its boiling point, making it non-volatile in steam.
(D) p-Amino phenol (para orientation with both OH and NH₂) — Also has intermolecular hydrogen bonding and hence is not steam volatile.

Step 3: Conclusion.
Compounds (A) and (B) exhibit intramolecular hydrogen bonding, which lowers their boiling points and makes them volatile with steam. Compounds (C) and (D) exhibit intermolecular hydrogen bonding, leading to higher boiling points and non-volatility.

Final Answer:
\[ \boxed{(A) \text{ and } (B) \text{ only}} \]