Chem 22 Final Exam Practice

Transcription

1 Chem 22 Final Exam Practice Questions taken from regular tests given during the previous semesters. Only one answer is correct unless the question says otherwise. The questions are somewhat scrambled with respect to topic, but one approach to studying for the final is to scramble them further, perhaps by cutting out individual questions and rearranging them. 1. Which of the following is the strongest acid? a. b. c. d. e. 2. Which of the following is/are acetals? More than one answer may be correct 3. What is the likeliest position of monochlorination when the compound below is reacted with Cl2 in the presence of AlCl3? a. b. c. d. e. it is impossible to tell 4. Which of the following is/are aromatic, assuming that they are or can be planar? More than one answer may be correct. 5. Which of the following is/are antiaromatic, assuming that they are planar? More than one answer may be correct. 6. Which of the following is expected to be the most reactive with Br2 in the presence of Fe? a. b. c. d. e. It is impossible to tell. Page 1 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

2 7. For which of the following processes would a blocking group be necessary? More than one may be correct. a. b. c. d. None of them. 8. Which of the following is the hydrolysis product in the reaction below? a. b. c. d. e. None 9. What is the mechanism of the following reaction? a. Electrophilic aromatic substitution b. Nucleophilic aromatic substitution (addition-elimination). c. Benzyne (elimination-addition) d. None of these 10. Which of the following is the strongest base? a. b. c. d. e. 11. Which of the following can successfully react in a self aldol addition reaction? More than one answer may be correct. Page 2 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

3 12. Which of the following is likeliest to produce the highest yield of the product shown from the initial reactant a. b. c. d. 13. Which reagents will convert the reactant to the product shown in an efficient manner? a. HCl(aq)/ b. SOCl2, pyridine c. NaCl/ d. 1. H3O + / ; 2. SOCl2 e. 1. NH3; 2. SOCl2 f. None of these will work. 14. What is the structure of the reactant in the following intramolecular aldol condensation? a. b. c. d. e. f. None of these. 15. Which of the following can successfully react in a self Claisen condensation? More than one answer may be correct. Page 3 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

4 16. What are the major products in the following reaction? a. b. c. both sets of products are formed in roughly equal amounts 17. What is the major organic product in the reaction below? a. b. c. d. e. f. none 18. Which of the following could be prepared via a Michael reaction using an enolate (not having to resort to a Stork enamine synthesis)? More than one answer may be correct. 19. What is the product of the following reaction? Ph 2 CuLi I a. (Z)-1-phenyl-2-pentene b. (Z)-1-phenyl-1-pentene c. (E)-1-phenyl-2-pentene d. (E)-1-phenyl-1-pentene e. 2-phenyl-1-pentene 20. Which of the following containing an acidic hydrogen that could be deprotonated by NaOH (would react with NaOH in a reaction with K>1)? More than one answer may be correct a. b. c. d. None will 21. Which would be the most reactive as the dienophile in a Diels-Alder reaction? a. b. c. d. e. Page 4 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

5 22. Which of the following can participate as the diene in a successful Diels-Alder reaction? Conformation changes are allowed. More than one answer may be correct. a. b. c. d. None can. 23. Which of the following is the ground-state LUMO for 1,3,5,7-octatetraene? a. b. c. d. e. f. g. none of these 24. Which of the following is expected to give a racemic mixture (equimolar mixture of enantiomers), or pretty close to that, as the major organic product(s)? More than one may be correct. a. b. c. d. None of them. 25. Which of the following is the reactant alkene in the reaction below? a. b. c. d. e. None of these 26. Which of the following is the kinetic product of the reaction below? a. b. c. d. e. None of these 27. Which of the following is the thermodynamic product of the reaction below? a. b. c. d. e. None of these Page 5 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

6 28. In which of the following has the starting material been oxidized? More than one answer may be correct. a. b. c. d. None of them 29. Which of the following could successfully be prepared by the reaction between an ester (any ester) and an excess of a Grignard reaction, followed by hydrolysis? More than one answer may be correct Which of the following reactions will successfully make the ether shown as the product in the reaction? By-products are deliberately not shown. More than one answer may be correct. a. b. c. 31. Which of the following represents the form of glutamic acid at ph 7.4? The pka values for the main carboxylic acid and protonated amine group are 2.19 and 9.67, respectively, while that of the side chain group is a. b. c. d. e. None 32. Which of the following is the most acidic? a. b. c. d. Page 6 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

7 33. Which of the following compounds has at least one lone pair that participates in aromaticity? More than one answer may be correct. a. b. c. d. none of them 34. To which compound does the pi molecular orbital diagram belong? a. b. c. d. e. 35. Which of the following is expected to be the most reactive in an electrophilic aromatic substitution reaction with nitric acid in the presence of sulfuric acid? (you are supposed to known the structures of these) a. benzoic acid b. benzaldehyde c. styrene d. anisole e. isopropyl benzene 36. What is the electrophile that reacted with a monohalosubstituted benzene to generate the following sigma complex intermediate? (only one of the resonance contributors of the intermediate is shown). a. FeBr5 (from Br2 with Fe) b. AlCl5 (from Cl2 with AlCl5) 37. Which of the following would be expected to faster with methanol in the presence of an acid catalyst? a. b. c. it is impossible to tell since they are both ketones 38. Which OH is part of a hemiacetal? (pick a or b or c or d or e based on labels in diagram) Page 7 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

8 39. Answer with the letters corresponding to the two reactants that would combine in acidic solution (but not too acidic) to make the compound drawn in the box. Your answer should consist of two, and only two, choices. More than two answers will result in zero credit for the question. a. b. c. d. 40. Which of the following will react with (R)-2-hexananol to produce a product that has the S-configuration at the chiral carbon? More than one answer may be correct. a. PBr3 b. SOCl2, pyridine c. TsCl, pyridine; then NaBr in acetone d. none of them 41. Which of the following compounds has the most nucleophilic carbon atom? a. CH3F b. (CH3)2Zn c. CH3Li d. (CH3)2Cu 42. Which of the following compounds could be made by the reaction between an aldehyde (any aldehyde; not necessarily the same one for all cases) and a Grignard reagent, followed by hydrolysis with water? More than one answer may be correct. a. b. c. d. none of them 43. Which of the following pairs of compounds could be isolated from each other? More than one answer may be correct. a. b. c. d. none 44. Which absorbs electromagnetic radiation at the longer wavelength to undergo a π π* transition? a. b. c. it is impossible to tell 45. The reaction below occurs with a. retention of configuration at both carbons b. inversion of configuration at both carbons c. retention of configuration at the carbon on the left side of the epoxide and inversion at the other carbon d. retention of configuration at the carbon on the right side of the epoxide and inversion at the other carbon Page 8 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

9 46. Which compound has the lowest pka? You are comparing the acidities of the most acidic proton in each compound. a. b. c. d. e. It is impossible to tell. 47. Which of the following has the highest pka for the carboxylic acid proton? a. b. c. d. it is impossible to tell. 48. The structure of D-galactose is in the box. Which structure represents L-galactose? a. b. c. d. e. None 49. Which of the following will decarboxylate when combined with aqueous acid and heated? More than one answer may be correct. will. 50. Which of the following can be made successfully by using the malonic ester synthesis, starting with diethyl malonate? More than one answer may be correct. could. 51. What is the correct name for the compound in the box? a. N-ethyl-N,1,3-trimethyl-1-pentanamine b. N-ethyl-N,1,3-trimethylpentanamine c. ethylisohexylmethylamine d. N-ethyl-N,4-dimethyl-2-hexanamine e. None of the above is correct. Page 9 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

10 52. The following reaction will not be successful. Why not? a. Ethoxide needs to be used as the base in the first step. b. LDA needs to be used as the base in the first step. c. The (CH3)3CBr won t react well in the second step. d. A third step involving hydrolysis needs to be added. e. The reaction will work just fine as written. 53. Which of the following can be prepared successfully from a mixed aldol condensation in a reasonable yield without resorting to a directed aldol, i.e. using LDA to make the enolate and then adding the other compound slowly to the solution of the enolate? More than one answer may be correct. could. 54. Which reactant is acting as the nucleophile in the reaction below? a. the ketone b. the enamine 55. What reagent/conditions would be best to use in step 1 in order to produce the product shown? a. NaH, 25 C b. LDA, -78 C c. NaOH, 25 C d, H3O Which of the following is expected to be the most reactive in an electrophilic substitution reaction with chlorine in the presence of aluminum chloride? e. benzophenone f. ethyl benzoate g. N-phenyl acetamide h. it is impossible to tell 57. The compound below will hydrolyze to a. aldehyde + secondary amine b. ketone + secondary amine c. ketone + primary amine d. aldehyde + primary amine e. none of these Page 10 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018

11 58. Which two compounds would react successfully in the presence of aluminum chloride to make the compound shown? Select two and only two answers. a. b. c. d. 59. Which species is/are intermediates in the mechanism shown? More than one answer may be correct. a. b. c. d. e. None 60. Which two compounds would react to make the compound in the box via an electrophilic aromatic substitution reaction? Select two, and only two. a. b. c. d. Page 11 of 11 Chem 22 Multiple-Choice Practice Last revised 2/9/2018