An organic compound 'X' forms a 2,4-DNP derivative and reduces Tollens' reagent, but does not reduce Fehling's solution. Which of the following combinations of starting material and reagent(s) can be used to prepare compound 'X'?

Step-by-step solution

The formation of a 2,4-DNP derivative indicates that compound 'X' is a carbonyl compound (aldehyde or ketone). Since 'X' reduces Tollens' reagent but does not reduce Fehling's solution, it must be an aromatic aldehyde, such as benzaldehyde. Aliphatic aldehydes reduce both Tollens' and Fehling's reagents, while ketones reduce neither. Let us evaluate the given preparation methods: Option (1): Toluene reacts with chromyl chloride ( CrO ₂ Cl ₂ ) in CS ₂ followed by acid hydrolysis to give benzaldehyde (Etard reaction)