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125. What is the major organic product obtained from the following reaction? O'Bu Di KOB TUOR 2 OB 20-16 A. 1 B. 2 C. 3 D. 4 126. What is the major organic product obtained from the following reaction? 0-160 O- cң, CH, CH₂ CH Naibu TOTOH 1 3 A. 1 B. 2 C. 3 D. 4 127. What is the major elimination product obtained from the following reaction? UCH CHE NOMO MOCH A. 1 B. 2 C. 3 D. 4 128. "Dehydrohalogenation" describes a reaction in the course of which a halogen is eliminated and a double bond is formed. What else is also eliminated? A. water B. hydronium ion C. hydrogen D. another halogen Page 21 of 27

82.Which product is obtained upon the reaction of (Z)-2-hexene with HBr? A. 2,3-Dibromohexane B. 2-Bromohexane C. 3-Bromohexane D. 2-Bromohexane and 3-bromohexane 83. The Cahn-Ingold-Prelog stereochemical designations used for the following substance are: A. 2R,45 B. 25,4R C. 2R, 4R D. 25,45 84. How many stereogenic centers are there in Lovastatin (Mevacor: a cholesterol lowering drug)? A. 5 B. 6 C. 7 D. 8 85. Which of the following (%) is the best leaving group? NHEN A. X = Iodide B. X = Chloride C. X = Bromide D. X = Fluoride Page 1 of 27

108. Which of the following statements regarding the E1 mechanism is wrong? A. Reactions by the El mechanism are unimolecular in the rate- determining step. B. Reactions by the El mechanism are generally first order. C. Reactions by the El mechanism usually occur in one step. D. Reactions by the El mechanism are multi-step reactions. 109. Which of the following statements about El elimination is FALSE? A. The rate of reaction = kl (alkyl halide] (NaOCH3). B. The reactivity order for alkyl halides (RX) is tertiary > secondary > primary. C. The rate is dependent on the leaving group. D. The reaction proceeds through a carbocation intermediate. 110. Identify the name of the mechanism for the following reaction, + Na uy A. E1 B. E2 C. SN1 D. S2 111. In the reaction of 1-chloropentane and potassium tert-butovide, the dominant mechanism is A. Sul. B. S2. C. EL. D. E2 Rank the following cations in order from most stable to least stable: cond 112. the Yin Bow A. 1>2>3 > 4 8. 4 > 3>2>1 C. 2 >1 > 4> 3 D. 3>4>2>1 113. Reaction of 2-chloro-2-methylpentane with methanol leads to three products. Which of the following products is NOT obtained from this reaction? A. 2-Methyl-2-pentanol B. 2-Methoxy-2-methylpentane C. 2-Methyl-1-pentene D. 2-Methyl-2-pentene it of att Page 18 of 27 APE DEN

101. Which of the following may be separated by ordinary physical methods? A. (R)-3-bromo-1-butene and (S)-3-bromo-1-butene B. cis-2-bromo-2-butene and trans-2-bromo-2-butene C. (2,3S)-1,2-dibromobutane and (25,3R)-1,2-dibromobutane D. (R)-2-bromobutane and (S)-2-bromobutane 102. Which of the following statements regarding the E2 mechanism is wrong? A. Reactions by the E2 mechanism are always bimolecular. B. Reactions by the E2 mechanism are generally second order. C. Reactions by the E2 mechanism usually occur in one step. D. Reactions by the E2 mechanism usually occur in two steps. 103. An optically active compound is composed of 75% of the (R) enantiomer and 25% of the (s) enantiomer. The enantiomeric excess (ee) is equal to A. 87.5 % B. 75 %. C. 50 %. D. 37.5 % 104. If a sample of 2-butanol has an enantiomeric excess of 60% of S2- butanol, how much of each isomer is present? A. 60% levorotatory and 40% dextrorotatory B. 80% levorotatory and 20% dextrorotatory C. 70% levorotatory and 30% dextrorotatory D. 66% levorotatory and 34% dextrorotatory 105. In the Ei reaction, how is the rate affected when the concentration of attacking nudeophile is doubled? A. The rate is doubled. B. The rate is halved. C. The rate quadruples. D. The rate is unchanged. 106. Which of the following may be separated by ordinary physical methods? A. a pair of identical molecules B. a pair of enantiomers C. a pair of diastereomers D. a pair of identical atoms 107. The reaction of 3-chloro-2,2-dimethylbutane and sodium lodide yields A. 3-lodo-2,2-dimethylbutane. B. 2-todo-3,3-dimethylbutane. C. 3-lodo-2,3-dimethylbutane. D. 2-todo-2,3-dimethylbutane. Page 17 of 27