Consider the following reaction sequence: Toluene [ (ii) H ₃ O ^+] (i) CrO ₂ Cl ₂, CS ₂ A [ 273-283 K ] Conc. HNO ₃ + Conc. H ₂ SO ₄ B The major product 'B' is:

Step-by-step solution

Step 1 is the Etard reaction. Toluene is oxidised by chromyl chloride ( CrO ₂ Cl ₂ ) in CS ₂ followed by acid hydrolysis to give benzaldehyde (Compound A). Step 2 is the nitration of benzaldehyde. The aldehydic group ( - CHO ) is an electron-withdrawing group and acts as a meta-directing, deactivating group in electrophilic aromatic substitution. Therefore, nitration of benzaldehyde with a nitrating mixture (concentrated HNO ₃ and concentrated H ₂ SO ₄ ) yields m -nitrobenzaldehyde as the major product (Compound B)