See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the reaction: Phenol reacts with acetone (CH3COCH3) in the presence of concentrated sulfuric acid. This is a well-known acid-catalyzed condensation reaction. Step 2 - Determine the molecular formula of the product: The product has molecular formula C15H16O2. Acetone is C3H6O and phenol is C6H6O. Two molecules of phenol (2 × C6H6O = C12H12O2) plus one molecule of acetone (C3H6O) give C15H18O3. The reaction loses two water molecules (2 × H2O = 2 × 18 = 36), giving C15H18O3 - 2H2O = C15H14O. That does not match. Let us recalculate: 2 phenol (C6H6O each) + acetone (C3H6O) → product + 2H2O. Atoms: C = 6+6+3 = 15, H = 6+6+6 = 18, O = 1+1+1 = 3. Minus 2H2O: H = 18-4 = 14, O = 3-2 = 1. That gives C15H14O, still not matching. Re-examine: the reaction is an electrophilic aromatic substitution where the carbonyl carbon of acetone is protonated and attacks the para position of two phenol rings. The product is 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A): (HO-C6H4)2C(CH3)2. Formula: 2×(C6H5OH) = C12H12O2, plus C(CH3)2 bridge from acetone minus its oxygen = C3H6. Total: C15H18O2, minus 2H (from two C-H bonds replaced at para positions) = C15H16O2. This matches the given molecular formula C15H16O2. Step 3 - Verify structure (b): Bisphenol A is 2,2-bis(4-hydroxyphenyl)propane, shown as HO-[phenyl]-C(CH3)2-[phenyl]-OH with OH groups at the para positions. Molecular formula: each 4-hydroxyphenyl = C6H5(OH) = C6H6O; two of them connected by C(CH3)2: C12H12O2 + C3H6 - 2H (lost from aromatic C-H) = C15H16O2. This matches. Step 4 - Reject other options: - Option (a): C(CH3)2(OC6H5)2 is a ketal/acetal-type product; formula C15H16O2 could fit numerically, but this would be formed by O-alkylation not C-alkylation, and conc. H2SO4 favors C-alkylation (Friedel-Crafts type) giving Bisphenol A, not a ketal. - Options (c) and (d): These are cyclohexadienone structures requiring ring dearomatization, which is not the primary product of phenol + acetone under H2SO4; also their structures and formulas do not correspond to the expected condensation product. Step 5 - Conclusion: The reaction of two moles of phenol with one mole of acetone under acid catalysis gives Bisphenol A (2,2-bis(4-hydroxyphenyl)propane), which is compound (b) with molecular formula C15H16O2. Therefore, the correct answer is B.