Question

12. Including endo/exo and R/S stereochemistry, what is the l enthalpy difference of the following reacting with chlorine and light making its major mono-chlorinated product selectivity Ratios C-H C-F C-Cl C-Br C-I х-х 98 10781 68 5338 136 2 95 106 80 68 53CI 58 103 91 106 79 65 5O Br 46888r b. -30 d. -25 e. not a.-d. a. -33 13. For the previous reaction, which step is most exothermic? a. the initiation step d. the termination step that would also form the same chlorine-ca c. -28 c. the second propagation step b. the first propagation step rbon bond e. not a.-d 14. Which is not a synthesis of an acyloin? но- е. not a.d. base b. C. R d. 15. What is the major product of the following reaction? C. d. e. not a.-d

Answer 1

Light leads to formation of radical Tertiary radical is most stable. but by selectivity ratio no. of tertiary carbon ratio = 2 times 5 = 10. No. of secondary carbon ratio = 4 times 4 = 16 hence chlorination occurs at secondary carbon Bond dissociation energy for secondary Ch = 99 k Cal/mol. BDE for cl_2 = 99 + 58 = 157 (Energy required) C - Cl & H-Cl bonds are formed hence energy released on formation of these bond = -(19 + 103) = -182 cal/mol. net energy range = Energy required for bond dissociation + energy released in bond formation = 157 + (-182) = -25 k cal/mol. D is correct.