Question

Phenol treated with chloroform in presence of sodium hydroxide, which further hydrolysed in presence of an acid results

• A. Salicyclic acid
• B. Benzene-1,2-diol
• C. Benzene-1, 3-diol
• D. 2-Hydroxybenzaldehyde

Answer 1

The Correct Option is D

The given reaction involves the conversion of phenol to 2-Hydroxybenzaldehyde (also known as salicylaldehyde). This reaction is known as the Reimer-Tiemann reaction. Let's break down the process step-by-step: 

1. When phenol (C₆H₅OH) is treated with chloroform (CHCl₃) in the presence of a strong base like sodium hydroxide (NaOH), an intermediate carbene (:CCl₂) is generated. This carbene is highly reactive.
2. The carbene intermediate attacks the ortho position (position 2) of the phenolic ring to form an intermediate compound.
3. Subsequently, this intermediate is hydrolyzed in the presence of an acid, typically hydrochloric acid (HCl), leading to the formation of 2-Hydroxybenzaldehyde.

Thus, the treatment of phenol with chloroform and sodium hydroxide followed by hydrolysis results in the formation of 2-Hydroxybenzaldehyde.

Here's why the other options are incorrect:

• Salicyclic acid is formed by the Kolbe-Schmitt reaction and not through the Reimer-Tiemann reaction.
• Benzene-1,2-diol (catechol) and Benzene-1,3-diol (resorcinol) are different compounds that do not form under the conditions specified in the question.

The correct answer is 2-Hydroxybenzaldehyde.

Answer 2

The reaction of phenol with chloroform in the presence of sodium hydroxide, followed by hydrolysis in an acidic medium, is known as the Reimer-Tiemann reaction. This reaction results in the formation of 2-hydroxybenzaldehyde (commonly known as salicylaldehyde). The reaction can be represented as:  
\(\text{Phenol} + \text{CHCl}_3 + \text{NaOH} \rightarrow 2\text{-Hydroxybenzaldehyde (salicylaldehyde)}\)

The reaction involves the introduction of a formyl group (-CHO) at the ortho position relative to the hydroxyl group (-OH), producing 2-hydroxybenzaldehyde.

The Correct Answer is: 2-Hydroxybenzaldehyde