Classification Of Organic Compounds

Step 1: Analyzing Reaction (A).
The reaction starts with benzoic acid (C₆H₅COOH).
- SOCl₂, Quinoline: SOCl₂ converts the carboxylic acid to the corresponding acyl chloride (C₆H₅COCl).
- H₂/Pd/BaSO₄: Hydrogenation of the acyl chloride reduces it to the corresponding aldehyde, benzaldehyde (C₆H₅CHO). Thus, Reaction (A) yields benzaldehyde.
Step 2: Analyzing Reaction (B).
The reaction starts with benzyl alcohol (C₆H₅CH₂OH).
- CrO₃/H₂SO₄: This reagent is used to oxidize alcohols to aldehydes.
- Benzyl alcohol is oxidized to benzaldehyde (C₆H₅CHO).
Step 3: Analyzing Reaction (C).
The reaction starts with anisole (C₆H₅OCH₃).
- NaBH₄: This is a mild reducing agent that typically reduces carbonyl compounds (like esters or ketones) to alcohols. - PCC: This reagent is used to oxidize alcohols to aldehydes.
- Anisole undergoes reduction to benzyl alcohol (C₆H₅CH₂OH) via NaBH₄, and then PCC oxidizes it to benzaldehyde (C₆H₅CHO).
Step 4: Analyzing Reaction (D).
The reaction starts with toluene (C₆H₅CH₃). - CrO₃: Chromium trioxide oxidizes methyl groups (CH₃) to the corresponding aldehyde, resulting in benzaldehyde. - (CH₃CO)₂O is a reagent typically used in Friedel-Crafts acylation, but in this reaction setup, it does not interfere with the oxidation step. The final product is benzaldehyde. Thus, Reaction (D) gives benzaldehyde.
Conclusion: The reactions that yield benzaldehyde are (A) and (D). Therefore, the correct answer is (C) (A) and (D).

Step 1: Understanding isoelectronic and isostructural concepts.
- Isoelectronic species have the same total number of electrons.
- Isostructural species have the same shape and hybridization.
Step 2: Analyzing the given pairs.
- and both have 22 valence electrons.
- Both species have a linear structure due to sp d hybridization with three lone pairs.