F 24- Mid-term III Practice Exam PDF

F 24- Mid-term III Practice Exam Dr. Neelam Lahankar Name: ______ __ Score: /100 INSRUCTIONS a) Using a pen, write your first and last name on the scantron and exam (page 1and 7, even...

F 24- Mid-term III Practice Exam Dr. Neelam Lahankar Name: ______ __ Score: /100 INSRUCTIONS a) Using a pen, write your first and last name on the scantron and exam (page 1and 7, even if you do not answer questions 19-23. Make sure both letters in your exam and scantron match. b) Answer questions 1-18 on the scantron using a pencil. (43 points each). Answer question 19-23 on the exam sheet. For questions 19-23, points are indicated in front of the questions. c) Submit your exam and scantron. d) It is your responsibility to transfer your answers to scantron in time and properly. Please note that no extra time can be given to transfer answers to scantron. e) In case of any type of plagiarism, the student will have to leave the examination and will get a 0 grade in the examination. f) No page from the examination is to be removed or taken outside the class. 1 F 24- Mid-term III Practice Exam Dr. Neelam Lahankar RELATIVE STRENGTH OF SELECTED ACIDS AND THEIR CONJUGATE BASES 2 F 24- Mid-term III Practice Exam Dr. Neelam Lahankar Please answer the following questions on the scantron. 1. I and II are: (n name indicates molecule with a continuous, unbranched chain) CH3 H2N OCH3 n-Bu NH2 OCH3 I II A) constitutional isomers. B) enantiomers. C) identical. D) diastereomers. E) not isomeric. 2. Which of the following statements is correct? A. 1,1-dicyclopentanyl ethane has a chiral center. B. 1,1-dicyclopentanyl ethane does not have a chiral center. C. has a chiral center. D. does not have a chiral center. I. A and B II. B and D III. C and D IV. A and D 3. How many stereoisomers can be drawn for 3,3,5-trimethylhept-1-en-6-yne? A. 0 B. 2 C. 3 D. 4 E. 6 4. Which of the following is (are) meso compound(s)? H CH3 CH3 Cl CH3 Cl H H Cl H Cl H Cl H Cl CH3 CH3 CH3 I II III A) I B) II C) III D) Both II and III E) Both I and III 3 F 24- Mid-term III Practice Exam Dr. Neelam Lahankar 5. Which of the following is (2S,3R)-2,3-dihydroxybutanal? 6. An attempt at synthesizing a certain optically active compound resulted in a mixture of its enantiomers. The mixture has an observed specific rotation of + 11.2. If it is known that the specific rotation of the (S) enantiomer is +39.8, determine the percentage of each isomer in the mixture. A. 64% (R), 36 % (S) B. 36 % (R), 64% (S) C. 60% (R), 40 % (S) D. 40% (R), 60 % (S) 7. Which one of the following is(are) enantiomer(s) of each other? A. B and C B. B only D C. A and B D. B and C E. A and C 8. The IUPAC name of the following compound is A. (3R, 4S) - 4-ethyl-3- methylheptane B. (3S, 4R) - 4-ethyl-3- methylheptane C. (3R, 4R) - 4-ethyl-3- methylheptane D. (3S, 4S) - 4-ethyl-3- methylheptane 9. What is IUPAC name of the following compound? A. (3R,5 R)-5-fluoro-3,5-dimethylhept-1-yne 4 F 24- Mid-term III Practice Exam Dr. Neelam Lahankar B. (3S,5 S)-5-fluoro-3,5-dimethylhept-1-yne C. (3 R,5S)-5-fluoro-3,5-dimethylhept-1-yne D. (3S,5 R)-5-fluoro-3,5-dimethylhept-1-yne E. (3 S,5 S)-5-fluoro-3,5-dimethylhex-1-yne 10. Which of the following statements regarding the SN1 mechanism is wrong? A. SN1 reactions are unimolecular. B. SN1 reactions are first order. C. The SN1 mechanism involves a single step. D. SN1 reactions are multistep reactions. 11. If the rate constant (k) for the SN2 reaction is 2.0 x 10-2 M-1s-1, the initial concentration of CH3Br is 0.2 M, and the initial concentration of OH- is 0.5 M, what is the initial rate of the reaction? A. 1.0 x 10-2 M/s B. 2.0 x 10-2 M/s C. 2.0 x 10-3 M/s D. 0.5 x 10-3 M/s 12. Which one of the following statements is wrong? A. In a group of nucleophiles in which the nucleophilic atom is the same, nucleophilicities parallel basicities. B. When the nucleophilic atoms are different, then nucleophilicities may not parallel basicities. C. I − is a stronger nucleophile in protic solvents, as its electron pair is more available to attack the substrate. D. F − is a stronger nucleophile in polar aprotic solvents, as its electron pair is more available to attack the substrate. E. All the above statements are correct. 13. The correct order of leaving group ability in nucleophilic substitution reaction is: A. Br− > Cl− > OH− > H− B. H− > OH− > Cl− > Br− C. Br− > OH− > Cl− > H− D. All will have the same leaving ability 14. Which is the most stable carbocation? 5 F 24- Mid-term III Practice Exam Dr. Neelam Lahankar 15. Arrange the following compounds in order of increasing SN1 reaction rates. A. I < II < III < V B. IV < I < III < II C. IV < I < II < III D. IV < II < III < I 16. Which of the following statements is correct? I. SN1 reaction is favored by polar, protic solvent. II. SN2 reaction is favored by polar, aprotic solvent. A. Only statement I is correct. B. Only statement II is correct. C. Both statements are wrong. D. Both statements are correct. 17. Arrange the following compounds in order of increasing SN2 reaction rates. A. III < I < II < IV B. I < III < II < IV C. III < I < IV < II D. IV < II < III < I 18. In which solvent following reaction occurs most rapidly? A. Water B. HF C. CH3COOH D. CH3COCH3 E. None of the above 6 F 24- Mid-term III Practice Exam Dr. Neelam Lahankar Name: Answer the following questions on these examination sheets: 19. How many chirality centers are in the following molecule? Circle those chirality centers. 20. Give the products and balanced equation for the following rection. Show all nonbonding electrons. 21. Outline an effective synthesis of butan-2-ol using the appropriate alkyl halide and nucleophile and any needed solvent and inorganic reagents. Show arrow pushing mechanism. Show all nonbonding electrons. 22. Draw the Fischer projection of 23. Draw a dash-wedge structure for (R)-2-bromo-3-methylbutane. 7