Identify the correct sequence of reagents to synthesize 2-chloro-4-nitrobenzoic acid from toluene as the major product.

Step-by-step solution

To synthesize 2-chloro-4-nitrobenzoic acid from toluene, the order of electrophilic aromatic substitution and oxidation reactions is critical because the directing nature of the substituent changes upon oxidation (from ortho/para-directing - CH ₃ to meta-directing - COOH ). Step 1: Nitration of toluene with conc. HNO ₃ and conc. H ₂ SO ₄ yields 4-nitrotoluene as the major isomer due to steric hindrance at the ortho position. Step 2: Chlorination of 4-nitrotoluene with Cl ₂ and FeCl ₃ takes advantage of the synergis