See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Step 1: Starting material is 4-nitrotoluene (methyl at C1, NO2 at C4). Step 2: Cl2/AlCl3 is electrophilic aromatic chlorination. The methyl group (ortho/para director) and NO2 group (meta director) both influence substitution. The methyl is at C1 and NO2 at C4. Positions ortho to methyl are C2 and C6; para to methyl is C4 (blocked by NO2). The NO2 group directs meta to itself, which corresponds to C1 and C7—but on a disubstituted ring, the combined directing effects place Cl at C2 (ortho to CH3, meta to NO2). This gives compound A = 2-chloro-4-nitrotoluene. Step 3: Fe/HCl then NaOH reduces NO2 to NH2 (via aniline intermediate, then free base). So B = 2-chloro-4-aminotoluene (i.e., 4-amino-2-chlorotoluene). Step 4: B and C share the same intermediate line, so C = B = 4-amino-2-chlorotoluene. Step 5: Br2/FeBr3 bromination of C (4-amino-2-chlorotoluene). The NH2 group is a strong ortho/para director. The ring has methyl at C1, Cl at C2, NH2 at C4. Positions available ortho/para to NH2: C3 (ortho to NH2 at C4), C5 (ortho to NH2), and C1 (para, blocked by CH3). C3 is between Cl (C2) and NH2 (C4)—somewhat hindered. C5 is ortho to NH2 at C4 and available. So Br enters at C5. Product D = 4-amino-5-bromo-2-chlorotoluene. Step 6: NaOH treatment of D. Here NaOH does not change the structure significantly for an aniline; E = D = 4-amino-5-bromo-2-chlorotoluene (or possibly used for deprotonation in next step). Step 7: H2SO4/NaNO2/H2O at low temperature = diazotization. The NH2 is converted to diazonium salt. F = 4-diazonium-5-bromo-2-chlorotoluene salt. Step 8: H3PO2/H2O = hypophosphorous acid, which replaces the diazonium group (N2+) with H (reductive removal). So the NH2/N2+ at C4 is replaced by H. Final product G = 2-chloro-5-bromotoluene (toluene with Cl at C2 and Br at C5, i.e., methyl at C1, Cl at C2, Br at C5). Step 9: Evaluating answer (a): The structure shown is a benzene ring with methyl at top (C1), Cl at C2 (ortho to methyl), and Br at C5 (para to Cl, meta to methyl). This matches 2-chloro-5-bromotoluene = the product G. Options (b) has Br ortho to methyl and Cl para — wrong regiochemistry. Options (c) and (d) show ketone substituents which are not part of this reaction sequence. Therefore, the correct answer is A.