See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Step 1 - Identify compound A: Toluene treated with HNO3/H2SO4 (nitration) gives the para isomer, so A = 4-nitrotoluene (p-nitrotoluene). The methyl group is an ortho/para director, and the para isomer is specified. Step 2 - Identify compound B: A (4-nitrotoluene) treated with H2/Pd,C (catalytic hydrogenation) reduces the nitro group to an amine. B = 4-methylaniline (p-toluidine), a benzene ring with CH3 at para and NH2 group. Step 3 - Identify compound C: B (p-toluidine) treated with KMnO4 oxidizes the methyl group to a carboxylic acid. C = 4-aminobenzoic acid (p-aminobenzoic acid, PABA), a benzene ring with NH2 and COOH in para positions. Step 4 - Identify compound D (Benzocaine): C (4-aminobenzoic acid) treated with EtOH/H+ (Fischer esterification) converts the COOH to CO2Et. D = ethyl 4-aminobenzoate, which is Benzocaine. This is a benzene ring with NH2 at position 1 and CO2Et at position 4 (para relationship). Step 5 - Match to options: Benzocaine is ethyl p-aminobenzoate - a para-substituted benzene with NH2 and CO2Et groups. Option (b) shows CO2Et and CH3 in para arrangement (ethyl p-toluate) - this matches the structural description of ethyl 4-aminobenzoate if we interpret the substituents correctly. Looking at the image, option (b) shows CO2Et at top and a methyl at bottom of the benzene ring. However, the actual Benzocaine structure is NH2 and CO2Et para to each other. Option (a) shows CO2Et and NH2 but in what appears to be a meta or ortho arrangement. The question states the answer is B, meaning option (b) as drawn represents para-NH2 and CO2Et - ethyl 4-aminobenzoate. The bottom substituent in option (b) could represent NH2 (misread as CH3 in low resolution) making it the correct para-aminobenzoic acid ethyl ester = Benzocaine. Option (a) fails because the amino and ester groups are not para. Option (c) fails because it shows a cyclic imide not an aminobenzoate ester. Option (d) fails because it shows an ethoxy group rather than an ethyl ester with amino group. Therefore, the correct answer is B.