Question

Consider the following reaction sequence:

The organic products ‘A’ and ‘B’ can be separated by:

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

Hint:

In phenol substitution reactions:

Ortho products often show intramolecular H-bonding.
Para products usually show intermolecular H-bonding.
Steam distillation is ideal when volatility differs due to hydrogen bonding.

Answer 1

The Correct Option is A

Concept:

Bromobenzene on treatment with NaOH at high temperature and pressure gives phenol.
Phenol on reaction with nitrosonium ion (\(\text{NO}^+\)) undergoes electrophilic substitution to give:

o-nitrosophenol and
p-nitrosophenol

o-nitrosophenol forms intramolecular hydrogen bonding, while p-nitrosophenol forms intermolecular hydrogen bonding.
Step 1: Identify the nature of products \(A\) and \(B\).

o-nitrosophenol is less associated due to intramolecular H-bonding and is more volatile.
p-nitrosophenol is strongly associated due to intermolecular H-bonding and is less volatile.

Step 2: Decide the method of separation. Because of the large difference in volatility: \[ \text{o-nitrosophenol is steam volatile, whereas p-nitrosophenol is not} \] Hence, they can be separated by steam distillation.
Conclusion: \[ \boxed{\text{Products A and B are separated by steam distillation}} \] Hence, the correct answer is (1).