PAGE 1 Short questions (1-8: 3 points each) 1. Estimate the pKa of the proton indicated. molecule with a proton attached to a carbon atom A. 50 B. 30 C. 15 D. 5 2. Which of the following compounds is likely to adopt a planar conformation? four molecules: A, B, C, D A. aromatic B. aromatic C. N tetrahedral D. Cannot be planar - H's bump into each other 3. Which of the following is the most likely to lose water upon protonation with HCl? four molecules: A, B, C, D A. aromatic B. none of others lose H2O after loss of H C. none of others lose H2O after loss of H D. none of others lose H2O after loss of H 4. What would be the major organic product of the reaction scheme shown? reaction scheme with two steps A. B. C. D. PAGE 2 5. Which of the following statements about benzene is INCORRECT? A. It undergoes electrophilic substitution reactions rather than electrophilic addition reactions. B. It is less reactive than hexatriene (CH2=CH-CH=CH-CH=CH2) C. The carbon-carbon bond lengths are all the same. D. The carbon-carbon bond lengths are longer than ethane. shorter 6. (3 points) Which of the following is the best description of a "catalyst"? Catalysts alter the kinetics of a reaction by: A. Making the products more stable B. Making the reaction more exothermic C. Lowering the energy of activation for the reaction D. Providing a source of fee radicals to initiate a reaction 7. What is the approximate magnitude of aromatic stabilization achieved by a simple compound like benzene? A. 5 kcal/mol B. 15 kcal/mol C. 25 kcal/mol D. 35 kcal/mol 8. Which of the following would be most reactive with Br2 in the presence of FeBra? PAGE 3 (9-11; 4 points each) 9. Rank the following compounds in order of increasing oxidation level (1 lowest, 4 highest) CH3CH2OH 2 CH3CHO 3 CH3CO2H CH3-CH3 10. Of compounds I and II, 11 is the stronger base. is the stronger acid and of compounds III and IV A. I and III B. I and IV III NH " IV ? C. II and III D. II and IV 11. Rank the following in order of reactivity in electrophilic aromatic substitution CF3 CH CF2H CH2F A B C D B A LEAST REACTIVE C MOST REACTIVE