JEE Chemistry 2024 Question with Solution

Given: Phenol is the starting material and salicylaldehyde is the required product.

Find: Which reagent combination converts phenol to salicylaldehyde.

This conversion is the Reimer-Tiemann reaction. In this reaction, phenol reacts with chloroform in the presence of sodium hydroxide, followed by acidic work-up.

The solution states that the correct reagent set is chloroform and NaOH.

Among the given options, the solution concludes that Option D corresponds to this reagent combination. However, the listed options show a discrepancy because option D is printed as HCl, NaOH in the listed options, while the solution explains the correct reagent should be CHCl₃, NaOH.

Using the solution, the correct option is taken as D.

Given: Salicylaldehyde has to be prepared from phenol.

Find: The correct reagents from the options.

The key named reaction is Reimer-Tiemann reaction, which introduces a formyl group at the ortho position of phenol.

1. Phenol is converted to phenoxide in the presence of NaOH.
2. The reaction requires chloroform as the carbon source for the aldehyde group.
3. Acidic work-up then gives salicylaldehyde.

The other options do not match this transformation:

• CO₂, NaOH corresponds to the Kolbe-Schmitt reaction, which gives salicylic acid.
• CCl₃, NaOH as written is not the standard reagent pair.
• HCl, NaOH does not provide the formyl group needed for salicylaldehyde.

Therefore, based on the extracted solution, the intended correct option is D.