See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: The van't Hoff factor (i) relates to the number of particles produced when a substance dissolves or reacts in solution. In this context, the question asks about the van't Hoff factor for the nitration reaction using the mixed acid system (HNO3 + H2SO4). Step 1: Understand the role of H2SO4 and HNO3 in nitration. The nitration mixture involves the following equilibrium/ionization steps: H2SO4 + HNO3 → H2NO3+ + HSO4- H2NO3+ → NO2+ + H2O H2O + H2SO4 → H3O+ + HSO4- Step 2: Write out all species generated from the interaction of HNO3 with H2SO4: HNO3 + 2H2SO4 → NO2+ + H3O+ + 2HSO4- Step 3: Count the number of particles produced from one molecule of HNO3: - Starting species: HNO3 (1 particle) - Products: NO2+ (nitronium ion) + H3O+ + 2HSO4- = 4 particles Step 4: Calculate the van't Hoff factor: i = number of particles after dissociation / number of original formula units i = 4 / 1 = 4 Step 5: Why other options fail: - (a) 2: Accounts for only one dissociation step, not complete. - (b) 3: Accounts for partial dissociation, not the full equation. - (d) 5: Overcounts the number of ionic species produced. Therefore, the correct answer is C.