See image — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the reaction type and substrate: The starting material is a three-carbon chain (2,4-dibromochlorobutane-like structure). More precisely, it is a molecule with: - C1 bearing CH3, H (wedge), and Br (dash) - C2 bearing H (wedge) and H (dash) - C3 bearing H (wedge), Cl (dash), and CH3 NaN3 is a source of the azide ion (N3-), a good nucleophile. Step 2 - Determine which leaving group reacts: Between Br and Cl, bromide is a far better leaving group in SN2 reactions because C-Br bonds are weaker and Br- is a more stable leaving group than Cl-. Therefore, NaN3 selectively displaces Br at C1. Step 3 - Determine stereochemistry of the SN2 reaction: SN2 proceeds with inversion of configuration (Waldhden inversion) at the carbon bearing the leaving group (C1). In the starting material, C1 has Br on the dash (back) and H on the wedge (front). After inversion, N3 replaces Br with inversion: N3 ends up on the wedge (front, left) and H remains but now effectively on the dash side, meaning N3 goes to the wedge position at C1. Step 4 - Identify the configuration at C3: C3 is not involved in the reaction, so its configuration is retained: H on wedge (left) and Cl on dash (right). Step 5 - Match to answer choices: - Option (c) shows: C1 with N3 on wedge (left) and H on dash (right) [inversion at C1 from Br-dash to N3-wedge], C3 with H on wedge (left) and Cl on dash (right) [unchanged]. This matches the SN2 inversion at C1 with retention at C3. Step 6 - Elimination of other options: - (a) has N3 on dash at C1, which would mean retention not inversion - incorrect. - (b) has N3 on wedge at C1 (correct inversion) but Cl on wedge at C3 (changed configuration at C3) - incorrect. - (d) has N3 on dash at C1 (retention) and Cl on wedge at C3 (changed) - incorrect. Therefore, the correct answer is C.