Package title: Solomons Test BankCourse Title: Solomons 11e Chapter Number: 6 Question type: Multiple choice 1) Select the rate law for the following reaction, e.g., CH3CH2CH2CHBrCH3 + OH CH3CH2CH2CHOHCH3 + Br - ( RBr ) A) Rate = k [RBr] B) Rate = k [RBr] [OH] C) Rate = k [RBr]2 [OH] D) Rate = k [RBr] [OH]2 E) Rate = k [RBr]2 [OH]2 Answer: B Topic: Reaction kinetics Section: 6.5 Difficulty Level: Easy 2) The rate equation for a nucleophilic substitution reaction of a secondary alkyl chloride (R-Cl) with I ion would be: A) Rate = k [RCl] B) Rate = k [I] C) Rate = k [RCl][I] D) Rate = k [RCl]2[I] E) Rate = k [RCl][I]2 Ans: C Topic: Reaction Kinetics Section: 6.5 Difficulty Level: Easy 3) Consider the SN2 reaction of butyl bromide with OH- ion. CH3CH2CH2CH2Br + OH- CH3CH2CH2CH2OH + Br- Assuming no other changes, what effect on the rate would result from simultaneously doubling 1 the concentrations of both butyl bromide and OH- ion? A) No effect. B) It would double the rate. C) It would triple the rate. D) It would increase the rate four times. E) It would increase the rate six times. Ans: D Topic: Reaction kinetics Section: 6.5 Difficulty Level: Medium 4) Consider the SN2 reaction of 2-iodopentane with CH3CO2 ion. I O O O NaI ONa Assuming no other changes, what effect on the rate would result from simultaneously doubling the concentrations of both 2-iodopentane and sodium acetate? A) No effect. B) It would double the rate. C) It would triple the rate. D) It would increase the rate four times. E) It would increase the rate six times. Ans: D Topic: Reaction kinetics Section: 6.5 Difficulty Level: Medium 5) Consider the SN2 reaction of 1-chloro-5-methylhexane with CN ion. Cl NaCN CN NaCl Assuming no other changes, what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and NaCN? 2 A) No effect. B) It would double the rate. C) It would triple the rate. D) It would increase the rate four times. E) It would increase the rate six times. Ans: D Topic: Reaction kinetics Section: 6.5 Difficulty Level: Medium 6) The reaction, CH3Cl + OH CH3OH + Cl H2O has the following thermodynamic values at 27.0 ºC: H = -75.3 kJ mol-1; S = 54.4 J K-1 mol-1. What is the value of G for this reaction? A) -73.8 kJ mol-1 B) -76.8 kJ mol-1 C) -59.0 kJ mol-1 D) +91.6 kJ mol-1 E) -91.6 kJ mol-1 Ans: E Topic: Free energy changes Sections: 6.7 Difficulty Level: Easy 7) Select the potential energy diagram that represents an exothermic (exergonic) reaction. 3 A) I B) II C) III D) IV E) V Ans: E Topic: Free energy diagrams Section: 6.7 Difficulty Level: Easy 8) Select the potential energy diagram that represents a single-step endothermic (endergonic) reaction. A) I 4 A) I B) II C) III D) IV E) V Ans: B Topic: Free energy diagrams Section: 6.B) II C) III D) IV E) V Ans: A Topic: Free energy diagrams Section: 6.7 Difficulty Level: Easy 9) Select the potential energy diagram that represents a two-step endothermic (endergonic) reaction.7 Difficulty Level: Easy 10) The difference in the bond energies of reactants and the transition state of a reaction is designated by the notation: 5 . A) H B) H‡ C) G D) G‡ E) S‡ Ans: B Topic: Free energy diagrams Section: 6. E) None of these choices.7 Difficulty Level: Easy 11) An increase in the temperature at which a reaction is carried out increases A) the collision frequency.7 Difficulty Level: Medium 12) Which will be true for any actual or potential nucleophilic substitution reaction? A) H is positive. C) G‡ is positive. Ans: D Topic: Activation energy Section: 6. Ans: C Topic: Transition state theory Section: 6. B) H is negative. D) More than one of these choices. The most important reason for this is that increasing the temperature 6 . D) G is positive. E) G is negative.7 Difficulty Level: Medium 13) Increasing the temperature of a chemical reaction usually increases greatly the rate of the reaction. B) the fraction of molecules with proper orientation. C) the fraction of molecules with energy greater than Eact. B) decreases the probability factor.7 Difficulty Level: Easy 14) What product(s) would you expect to obtain from the following SN2 reaction? H H CH3ONa ? CH3 Br CH3OH H H H OCH3 CH3O H CH3 OCH3 CH3 H H Br I II III A) I B) II C) An equimolar mixture of I and II. D) III E) None of these choices. D) decreases the energy of activation. C) increases the fraction of collisions with energy greater than Eact. Ans: B Topic: Predicting products Section: 6. Ans: C Topic: Activation Energy Section: 6. E) makes the reaction more exothermic.8 Difficulty Level: Easy 15) The major product of the following reaction would be: 7 .A) increases the collision frequency. CH2Cl OH H OCH3 ? SN2 CH3 CH2OH CH2OH H3CO H H OCH3 CH3 CH3 I II CH2Cl CH2Cl HO H H OH CH3 CH3 III IV A) I B) II C) III D) IV E) An equimolar mixture of I and II. C) The single transition state represents the point of maximum free energy of the reaction.8 Difficulty Level: Easy 16) A true statement about the transition state(s) of an SN2 reaction is: A) The two transition states are of unequal energy. E) The transition state will always have a net charge of -1.8 Difficulty Level: Hard 17) The rate equation for a nucleophilic substitution reaction of a tertiary alkyl bromide (R-Br) with I ion would be: 8 . Ans: C Topic: Generalities Sections: 6.7 and 6. D) Existence of this transition state implies an exothermic reaction. B) The transition states precede and follow an unstable reaction intermediate. Ans: B Topic: Predicting products Section: 6. NaI NaCl Cl I Assuming no other changes. Ans: B Topic: Reaction Kinetics Section: 6.10 Difficulty Level: Easy 18) Consider the reaction of 2-chloro-2-methylpentane with sodium iodide. C) It would triple the rate.1 M] sodium cyanide with [0. B) It would double the rate.2 M] and the concentration of the alkyl bromide is decreased to [0.1 M] 2-bromo-2-methylpropane is 1. D) It would quadruple the rate. what would be the effect on the overall rate if the concentration of sodium cyanide is increased to [0.05 M]? a) the rate will increase by a factor of 2 b) the rate will decrease by a factor of 2 c) the rate will increase by a factor of 10 d) the rate will decrease by a factor of 10 e) the rate will remain unchanged Ans: B 9 .10 Difficulty Level: Hard 19) If the rate of reaction of [0.9 and 6. how would it affect the rate if one simultaneously doubled the concentration of 2-chloro-2-methylpentane and sodium iodide? A) No effect.2 x 10-3 M/s.9 and 6.A) Rate = k [RBr] B) Rate = k [I] C) Rate = k [RBr][I] D) Rate = k [RBr]2[I] E) Rate = k [RBr][I]2 Ans: A Topic: Reaction Kinetics Section: 6. E) It would increase the rate five times. Topic: Reaction kinetics Section: 6. contains how many electrons? A) 0 B) 1 C) 2 D) 3 E) 4 Ans: A Topic: Carbocations Section: 6. contains how many electrons? A) 0 B) 1 C) 2 D) 3 E) 4 Ans: A 10 .11 Difficulty Level: Easy 21. The p orbital of a methyl cation. A) sp4 B) sp3 C) sp2 D) sp E) s Ans: C Topic: Carbocations Section: 6. (CH3)2CH+.9 and 6. CH3+.11 Difficulty Level: Easy 22) The p orbital of the charged carbon in the isopropyl cation.10 Difficulty Level: Medium 20) The hybridization state of the charged carbon in a carbocation is ___. Which of the following would be true? A) The reaction would take place only with inversion of configuration at the stereogenic center.8 and 6.11 Difficulty Level: Easy 23) Which of the following reactions proceeds with inversion of configuration at the carbon bearing the leaving group? A) SN2 B) SN1 C) E2 D) E1 E) All of these answer choices are correct. B) An SN1 reaction would take place with retention of configuration at the stereogenic center. B) The reaction would take place only with retention of configuration at the stereogenic center.12 Difficulty Level: Easy 24) Consider the substitution reaction that takes place when (R)-3-bromo-3-methylhexane is treated with methanol. D) No reaction would take place.8 and 6.Topic: Carbocations Section: 6. stereochemistry of SN reactions Sections: 6.12 Difficulty Level: Medium 25) Consider the substitution reaction that takes place when (R)-3-bromo-3-methylhexane is treated with sodium methoxide. Which of the following would be true? A) An SN2 reaction would take place with inversion of configuration at the stereogenic center. D) An SN1 reaction would take place. C) The reaction would take place with racemization. Ans: A Topic: Stereochemistry of SN/E reactions Sections: 6. accompanied by an E1 reaction. C) An SN1 reaction would take place with racemization of configuration at the stereogenic center. E) The alkyl halide does not possess a stereogenic center. Ans: C Topic: Predicting mechanism. affording a complex 11 . Ans: D Topic: Predicting mechanism.8 and 6. Ans: B Topic: Predicting mechanisms. products Section: 6. E) An E2 reaction would take place. stereochemistry of SN reactions Sections: 6.8 and 6. E) An E2 reaction would take place. the following reaction is an example of what type of mechanism? A) SN1 B) SN2 C) E1 D) E2 E) More than one of these choices. B) An SN1 reaction would take place with retention of configuration at the stereogenic center. D) An SN1 reaction would take place. during which the stereogenic center is lost.mixture of products. during which the stereogenic center is lost. accompanied by an E1 reaction. Ans: E Topic: Predicting mechanism. affording a complex mixture of products. stereochemistry of SN reactions Sections: 6.13 Difficulty Level: Easy 12 .12 Difficulty Level: Medium 27) By analyzing the starting material and the product(s).12 Difficulty Level: Medium 26) Consider the substitution reaction that takes place when (R)-3-iodo-3-methylheptane is treated with sodium acetate (CH3CO2Na). Which of the following would be true? A) An SN2 reaction would take place with inversion of configuration at the stereogenic center. C) An SN1 reaction would take place with racemization of configuration at the stereogenic center. when applied to nucleophilic substitutions and elimination reactions. products Section: 6. 13 . Ans: A Topic: Predicting mechanisms. Ans: B Topic: Predicting mechanisms.28) By analyzing the starting material and the product(s).13 Difficulty Level: Easy 30) The Hammond-Leffler postulate. products Section: 6.13 Difficulty Level: Easy 29) By analyzing the starting material and the product(s). the following reaction is an example of what type of mechanism? A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. the following reaction is an example of what type of mechanism? A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. B) polar aprotic solvents strongly accelerate the rate of SN2 processes. states that A) a negatively-charged nucleophile is stronger than its conjugate acid. C) bimolecular nucleophilic substitutions are 2nd order kinetically.4-diiodo-2.10 mol) is treated with 0. the transition state has zero charge overall. C) Formation of the transition state is an exothermic reaction. D) Necessarily.13 Difficulty Level: Medium 32) Which is a true statement concerning the transition state of the rate-determining step of an SN1 reaction? A) Structurally. E) More than one of these choices. it closely resembles the carbocation intermediate.2-dimethylbutane (0.10 mol of NaCN in dimethyl sulfoxide at 30C. E) elimination reactions will always compete with nucleophilic substitution reactions. Ans: D Topic: Hammond-Leffler postulate Section: 6.13 Difficulty Level: Easy 31) When 1. Ans: A 14 . B) Both covalent bond-breaking and bond-making are occurring. products Section: 6. D) the transition state for an endergonic reaction step (one accompanied by an increase in free energy) resembles the product of that step. the product formed is: I NC A) CN I B) CN NC C) I D) Ans: B Topic: Predicting mechanisms. Topic: Hammond-Leffler postulate Section: 6. products Section: 6.13 Difficulty Level: Hard 35) You want to synthesize 3-methyl-2-pentene from 2-chloro-3-methylpentane. Ans: B Topic: Synthesis. CH3CO2H. reagent selection Section: 6. Which reagent would you use? A) HCl.13 Difficulty Level: Medium 33) By analyzing the starting material and the product(s). heat 15 .13 Difficulty Level: Hard 34) Which of the following alkyl bromide isomers would most readily undergo an SN2 reaction? a) bromocyclobutane b) 4-bromo-1-butene c) 3-bromo-1-butene d) 1-bromo-1-butene e) All will react at the same rate. Ans: A Topic: Predicting mechanisms. heat B) NH3(aq). 25oC C) CH3CO2Na. the following reaction is possibly an example of what type of mechanism? + Br N3 N3 A) SN1 B) SN2 C) E1 D) E2 E) More than one of these choices. CH3CH2OH. though primary.13 Difficulty Level: Hard 36) Which alkyl chloride. heat E) CH3CH2OH.D) CH3CH2ONa.13 Difficulty Level: Easy 37) Which alkyl halide would be most reactive in an SN1 reaction? 16 . reagent selection Section: 6. is essentially unreactive in SN2 reactions? Cl A) B) Cl C) Cl Cl D) Cl E) Ans: E Topic: Steric hindrance Sections: 6. heat Ans: D Topic: Synthesis. What is the explanation that best describes this transformation? a) an SN2 reaction has occurred with inversion of configuration b) racemization followed by an SN2 attack c) an SNI reaction has taken over resulting in inversion of configuration d) an SN1 reaction has occurred due to carbocation formation e) an SN1 reaction followed by an SN2 “backside” attack Ans: D Topic: Kinetics and Mechanism Section: 6.8. C) a decrease in the probability factor.13 Difficulty Level: Easy 39) An increase in the kinetic energy of reacting molecules results in A) a decrease in reaction rate.13 Difficulty Level: Easy 38) Reaction of (R)-2-chloro-4-methylhexane with excess NaI in acetone gives racemic 2-iodo- 4-methylhexane. 6. Br Br Br I II III Br Br IV V A) I B) II C) III D) IV E) V Ans: D Topic: Kinetics Section: 6. D) an increase in the reaction rate. B) an increase in the probability factor. 17 . 13 Difficulty Level: Easy 42) Which of the following is not a nucleophile? A) H2O B) CH3O- C) NH3 18 .7 and 6. nucleophiles Sections: 6.3 and 6.8 and 6.13 Difficulty Level: Medium 41) Identify the nucleophile in the following reaction: 2 H2O + RX ROH + H3O+ + X A) X- B) H3O+ C) ROH D) H2O E) RX Ans: D Topic: Generalities.13 Difficulty Level: Medium 40) Which alkyl halide would you expect to undergo an SN2 reaction most slowly? A) 1-bromohexane B) 1-bromo-2-methylpentane C) 1-bromo-3-methylpentane D) 1-bromo-4-methylpentane E) 1-bromo-2.2-dimethylbutane Ans: E Topic: Kinetics Sections: 6.E) no changes. Ans: D Topic: Transition State theory Sections: 6. .3 and 6. ..13 Difficulty Level: Easy 44) Identify the nucleophile in the following reaction: 2R’OH + RX ROR’ + [R’OH2]+ + X- A) X B) [R’OH2] C) ROR’ D) R’OH E) RX Ans: D 19 .. Ans: D Topic: Generalities. .. H. . . 2 :CN: :OH :OCH . H. :O:N::O . N:O:H . 2CH 2S: . . .. I II III .3 and 6.....13 Difficulty Level: Easy 43) Ambident nucleophiles are ones which can react with a substrate at either of two nucleophilic sites. IV V A) I B) II C) III D) IV E) V Ans: B Topic: Nucleophiles Sections: 6. ... Which of the following is not an ambident nucleophile? . . nucleophiles Sections: 6.D) NH4+ E) All are nucleophiles.. .. nucleophiles Sections: 6.3 and 6.3 and 6.3 and 6.13 Difficulty Level: Medium 45) Which is the strongest nucleophile? A) OH- B) CH3CH2O- C) D) CH3CH2OH E) H2O Ans: B Topic: Nucleophiles Sections: 6.Topic: Generalities.13 Difficulty Level: Medium 47) Which SN2 reaction would you expect to take place most rapidly? Assume that the concentrations of the reactants and the temperature are the same in each instance.13 Difficulty Level: Medium 46) Rank the following in terms of nucleophilic strength: a) I>II>III>IV>V b) V>IV>III>II>I c) I>IV>II>III>V d) V>I>IV>II>III e) I>II>IV>V>III Ans: C Topic: Nucleophiles Sections: 6. A) CH3S + CH3I CH3SCH3 + I 20 . B) H CH3SH + CH3I S + I H3C CH3 C) CH3O + CH3I CH3OCH3 + I D) H CH3OH + CH3I O + I H3C CH3 E) CH3S + CH3Cl CH3SCH3 + Cl Ans: A Topic: Nucleophilicity. 6.13 Difficulty Level: Medium 48) Which is not a polar aprotic solvent? O C A) H3C CH3 B) H3C C N O S C) H3C CH3 O C CH3 H N D) CH3 CH3 CH E) H3C OH Ans: E Topic: Generalities. leaving groups Sections: 6. 6.8.3. solvent effects 21 . X = I II. solvent effects Section: 6. Ans: A Topic: Generalities.13 Difficulty Level: Easy 50) Consider an SN2 reaction of NaSH in a polar aprotic solvent with (CH3)2CHCH2CH2X. Topic: Generalities. X = Br III.13 Difficulty Level: Easy 51) Which is the weakest nucleophile in polar aprotic solvents? A) I- B) Br- C) Cl- D) F- E) All of these choices are equally strong nucleophiles.Section: 6.13 Difficulty Level: Easy 49) Which is a polar aprotic solvent? A) 2-methylhexane B) CCl4 C) NH3(l) D) CH3CH2CH2OCH2CH2CH3 E) 2-methyl-2-propanol Ans: D Topic: Generalities. regardless of the type of solvent used. solvent effects 22 . solvent effects Section: 6. What would be the relative order of reactivity for the following X substituents? I. X = Cl IV X = F a) I > II > III > IV b) II > I > IV > III c) IV > III > II > I d) III > I > II > IV e) None of these choices. solvent effects Sections: 6. Ans: D Topic: Nucleophile.13 Difficulty Level: Easy 54) Which ion is the strongest nucleophile in an aprotic solvent such as dimethylsulfoxide? A) I- B) Br- C) Cl- D) F- E) All of these choices are equal.13 Difficulty Level: Easy 52) Which is the weakest nucleophile in polar protic solvents? A) I- B) Br- C) Cl- D) F- E) All of these choices are equally strong nucleophiles.Sections: 6. solvent effects Sections: 6. regardless of the type of solvent used. Ans: D Topic: Generalities. solvent effects Sections: 6. Ans: D Topic: Generalities.13 Difficulty Level: Easy 53) Which ion is the strongest nucleophile in aqueous solution? A) F- B) Cl- C) Br- D) I- E) All of these choices are equally strong.13 23 . 13 Difficulty Level: Easy 56) Considering the relative solvation of reactants and the transition states of substitution reactions of these reactants. Ans: A 24 .+ RX RY + X:- C) Y: + RX+ RY+ + X: D) Y:. Ans: A Topic: Leaving groups Sections: 6. A) Y: + RX RY+ + X:- B) Y:.13 Difficulty Level: Medium 57) Which is the most reactive nucleophile in DMF (structure shown below)? O C CH3 H N CH3 A) F- B) Cl- C) Br- D) I- E) All of these choices are equally reactive. solvent effects Sections: 6.4 and 6.+ RX+ RY + X: E) RX+ R+ + X: Ans: A Topic: Generalities.Difficulty Level: Medium 55) Which alkyl halide would you expect to react most slowly when heated in aqueous solution? A) (CH3)3C-F B) (CH3)3C-Cl C) (CH3)3C-Br D) (CH3)3C-I E) All of these choices would react at the same rate. predict which general type of reaction would be most favored by the use of a polar solvent. + CH3CH2–Br CH3CH2–I + Br- B) I. acting in a protic solvent. + (CH3)2CH-Cl (CH3)2CHOH + Cl- D) HO. + CH3-Cl CH3OH + Cl- B) HO.+ CH3CH2–Cl CH3CH2–Br + Cl- E) Br. 6.+ CH3CH2–F CH3CH2–Br + F- Ans: A Topic: Leaving groups. solvent effects Sections: 6. nucleophiles Sections: 6. solvent effects Sections: 6.+ CH3CH2–Cl CH3CH2–I + Cl- C) I.3.3. + (CH3)3CCH2-Cl (CH3)3CCH2OH + Cl- Ans: A 25 . 6.+ CH3CH2–F CH3CH2–I + F- D) Br. 6.13 Difficulty Level: Easy 58) Which of these species. + (CH3)3C-Cl (CH3)3COH + Cl- E) HO.3.Topic: Nucleophile. exhibits greater nucleophilic activity than expected on the basis of its basicity? A) OH- B) CH3O- C) SH- D) Cl- E) H2O Ans: C Topic: Nucleophile.13 Difficulty Level: Medium 59) Which SN2 reaction will occur most rapidly in a mixture of water and ethanol? A) I.13 Difficulty Level: Medium 60) Which SN2 reaction will occur most rapidly in aqueous acetone solution? Assume concentrations and temperature are the same in each instance. A) HO. + CH3CH2-Cl CH3CH2OH + Cl- C) HO. 6.13 Difficulty Level: Hard 63) Which of the following solvents will best promote a nucleophilic reaction between NaCN and 1-bromopropane? a) H2O/MeOH mixture b) H2O c) MeCN d) HF(aq) e) running with no solvent 26 . d) Strong bases are always good nucleophiles e) None of these answer choices are correct. E) Actually. c) The greater the strength of a nucleophile. kinetics Sections: 6.3.13 Difficulty Level: Hard 62) Which of the following is not true concerning the strength of a nucleophile? a) Nucleophilicity may not parallel basicity.3.13 Difficulty Level: Medium 61) The relative nucleophilicities of species do not necessarily parallel the relative basicities of the same species because A) not all nucleophiles are bases. C) nucleophilicity is a thermodynamic matter. Ans: D Topic: Nucleophilicity Sections: 6. 6. nucleophilicity is a matter of kinetics. and vice versa. D) basicity is a thermodynamic matter.Topic: Predicting mechanism. the faster an SN2 reaction will occur. b) Negatively charged nucleophiles are always more reactive than their conjugate acids. Ans: D Topic: Nucleophilicity Sections: 6.3. B) experimental measurements of sufficient accuracy are not available to make the comparisons. basicity is a matter of kinetics. 6. the relative values do parallel one another. 3. solvent effectsh Sections: 6.3.Ans: C Topic: Predicting mechanism. solvent effects Sections: 6. nucleophilicity. solvent effects Sections: 6. Ans: E Topic: Predicting mechanism.13 Difficulty Level: Medium 64) Which of the following nucleophiles will react the fastest with tert-butyl bromide in ethanol? a) F- b) Br- c) I- d) Cl- e) All react at about the same rate.13 Difficulty Level: Hard 65) Which of the following nucleophiles will react the fastest with 1-bromoptopane in ethanol? a) SH- b) OH- c) H2O d) H2S e) All react at about the same rate.3. 6. 6. kinetics.13 Difficulty Level: Medium 66) Which SN2 reaction would take place most rapidly? H2O OH + CH3Cl o CH3OH + Cl A) 25 C O O H2O + CH3Cl + Cl B) H3C O 25oC H3CO CH3 H2O H2O + CH3Cl CH3OH2 + Cl C) 25oC 27 . Ans: A Topic: Predicting mechanism. 6. SNa S I Na + I A) C6H5S- B) Na+ C) CH3CH2I D) C6H5SCH2CH3 E) I- Ans: E Topic: Generalities.4 and 6.13 Difficulty Level: Easy 28 . 6. Ans: A Topic: Leaving group Sections: 6. 6.13 Difficulty Level: Easy 68) Identify the leaving group in the following reaction. 6. nucleophilicity Sections: 6.2. E) None of these choices. 6.4.8. H CH3OH CH3OH + CH3Cl O + Cl D) 25oC H3C CH3 H2O SH + CH3Cl CH3SH + Cl E) 25oC Ans: E Topic: Kinetics. leaving group Sections: 6.3.13 Difficulty Level: Medium 67) Which of the following is a feasible substitution reaction? A) CH3CH2Cl + NaBr CH3CH2Br + NaCl B) CH3CH3 + NaCN CH3CH2CN + NaH C) CH3CH2Cl + NaOH CH2=CH2 + H2O + NaCl D) More than one of these choices. Ans: B Topic: Leaving groups Sections: 6.13 Difficulty Level: Easy 70) Which nucleophilic substitution reaction would be unlikely to occur? A) HO + CH3CH2–I CH3CH2–OH + I B) I + CH3CH2–H CH3CH2–I + H C) CH3S + CH3–Br CH3S–CH3 + Br D) All of these choices would be unlikely to occur.13 Difficulty Level: Easy 71) Which of the following would be most reactive in an SN2 reaction? Br A) B) Br C) Br Br D) 29 . CH3OH + CH3OH2 CH3OCH3 + H2O H A) CH3OH B) CH3OH2+ C) CH3OCH3 D) H2O E) None of these choices.4 and 6.69) Identify the leaving group in the following reaction. E) None of these choices would be unlikely to occur. Ans: D Topic: Leaving groups Sections: 6.4 and 6. Ans: A Topic: Leaving groups Sections: 6.4 and 6. leaving group Sections: 6.13 Difficulty Level: Medium 74) Which nucleophilic substitution reaction is not likely to occur? A) I + CH3CH2–Cl CH3CH2–I + Cl B) I + CH3CH2–Br CH3CH2–I + Br C) I + CH3CH2–OH CH3CH2–I + OH 30 .4 and 6.4 and 6.E) Br Ans: D Topic: Leaving groups Sections: 6.13 Difficulty Level: Medium 73) Which of the following is not a good leaving group? A) C2H5O B) Cl C) I D) CH3CO2 E) All of these choices are good leaving groups.13 Difficulty Level: Easy 72) Which of the following is the poorest leaving group? A) H B) CH3O C) H2O D) OH E) NH2 Ans: E Topic: Generalities. 18 Difficulty Level: Medium 76) Which mechanism best describes the chemical process shown below? a) SN2 b) E1 c) E2 d) SN1 e) None of these choices. products Section: 6. Ans: B Topic: Predicting mechanisms.D) CH3O + CH3CH2–Br CH3CH2–OCH3 + Br E) OH + CH3CH2–Cl CH3CH2–OH + Cl Ans: C Topic: Leaving groups Sections: 6. products Section: 6. the following reaction is possibly an example of what type of mechanism(s)? + Cl A) SN1 B) SN2 C) E1 D) E2 E) More than one of the above Ans: E Topic: Predicting mechanisms.3.13 Difficulty Level: Medium 75) By analyzing the starting material and the product.4. 6.18 31 . 6. the following reaction is an example of what type of mechanism? Br A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. Ans: D Topic: Predicting mechanisms. Ans: E Topic: Predicting mechanisms. would afford a product mixture consisting of more than one elimination product? A) 1-bromo-3.Difficulty Level: Medium 77) By analyzing the starting material and the product(s).18 Difficulty Level: Hard 79. products Section: 6.18 Difficulty Level: Medium 78) By analyzing the starting material and the product(s).13 and 6.3-dimethylpentane 32 . when treated with sodium ethoxide in ethanol. the following reaction is possibly an example of what type of mechanism? HO O A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. products Sections: 6. Which alkyl halide. C) when 3 alkyl halides are used as substrates.3-dimethylpentane E) None of these choices would yield more than one elimination product. Ans: E Topic: Generalities Section: 6..18 Difficulty Level: Medium 80) Elimination reactions are favored over nucleophilic substitution reactions A) at high temperatures. D) when nucleophiles are used which are strong bases and the substrate is a 2 alkyl halide.3-dimethylpentane C) 2-bromo-3.B) 1-bromo-2. i.e. E) in all of these cases. B) when tert-butoxide ion is used. Br HC C: Na ? I II III HC CH IV A) I B) II C) III D) IV 33 .18 Difficulty Level: Medium 81) What would you expect to be the chief organic product(s) when tert-butyl bromide reacts with sodium acetylide. Ans: C Topic: Predicting products Section: 6.4-dimethylpentane D) 2-bromo-3. products Section: 6.e. Ans: D Topic: Predicting mechanisms.15 and 6. i.E) None of these choices.18 Difficulty Level: Hard 83) Suggest a reagent to perform the following transformation: 34 . Br C: Na ? I II III HC CH HC CH IV V A) I B) II C) III D) IV E) V Ans: D Topic: Predicting mechanisms. products Section: 6.18 Difficulty Level: Hard 82) What would you expect to be the chief organic product(s) when 2-bromo-2-methylpentane react(s) with sodium propynide.15 and 6.. by substitution of the alkyl group. H2O b) NaH. by predominantly SN2 B) II.a) NaOH. none of these products are likely to be obtained as major products. THF c) NaOMe. MeOH d) t-butoxide. because elimination will probably predominate. E) Actually. by predominantly SN1 D) III. 65oC H H O O H H O H H H Cl I II III A) I.15 and 6. by predominantly SN2 C) an equimolar mixture of I and II. Ans: E Topic: Predicting mechanisms. leading to the formation of an alkene. products Section: 6. t-butanol e) Ethanol Ans: D Topic: Predicting reagents for mechisms Section 6.18 Difficulty Level: Medium 85) The major product(s) of the following reaction is(are): 35 . rather than substitution of the chloro group.18 Difficulty: Medium 84) What major product(s) are likely to be obtained from the following reaction? H CH3CH2ONa ? Cl CH3CH2OH. Ans: B Topic: Predicting mechanisms. H H NaI. CH3CH2OH 25oC CH3 Cl H H H I H H CH3 I CH3 H CH3 CH3 OCH2CH3 I II III IV A) I B) II C) III D) IV E) Equal amounts of I and II.8 and 6.18 Difficulty Level: Easy 86) What would be the major product of the following reaction? CH2Cl OH H CH3 SN2 CH2OH CH2OH H3C H H CH3 I II CH2Cl CH2Cl HO CH3 H OH III IV A) I B) II C) III D) IV E) An equimolar mixture of I and II. 36 . products Section: 6. Ans: A Topic: Predicting products Section: 6.Ans: B Topic: Predicting products Section: 6.8 and 6.18 Difficulty Level: Easy 88) What would be the major product(s) of the following reaction? O CH3SNa O S O CH3SH SCH3 SCH3 I II III IV 37 .18 Difficulty Level: Easy 87) What would be the major product(s) of the following reaction? CH3CH2CO2Na I CH3CH2CO2H O2CCH2CH3 O2CCH2CH3 O2CCH2CH3 I II III IV A) I B) II C) III D) IV E) None of these choices.8 and 6. 8 and 6.18 Difficulty Level: Easy 90) What would be the major product of the following reaction? 38 .18 Difficulty Level: Easy 89) What would be the major product(s) of the following reaction? Br NaI Acetone I I I I II III IV A) I B) II C) III D) IV E) None of these choices.A) I B) II C) III D) IV E) More than one of these choices. Ans: B Topic: Predicting products Sections: 6. Ans: C Topic: Predicting products Section: 6.8 and 6. Ans: B Topic: Predicting mechanisms. products Sections: 6.18 Difficulty Level: Easy 91) The product(s) for the following reaction would mainly be dictated by which mechanism? NaCN DMF Cl A) SN1 B) SN2 C) E1 D) E2 E) None of these choices.8 and 6. Ans: C Topic: Predicting mechanisms. H3C H C H Br 25oC H3C H H3C CN H CN H Br I II H3C CN H3C H H H NC Br III IV A) I B) II C) III D) IV E) Equal amounts of I and III.8 and 6.18 Difficulty Level: Easy 39 . products Sections: 6. 92) Reaction of sodium ethoxide with 1-bromopentane at 30C yields primarily: A) CH3CH2CH2CH=CH2 B) CH3CH2CH=CHCH3 C) CH3CH2CH2CH2CH3 D) CH3CH2CH2CH2CH2OH E) CH3CH2CH2CH2CH2OCH2CH3 Ans: E Topic: Predicting mechanisms.8 and 6. products Sections: 6. products Sections: 6.18 Difficulty Level: Easy 93) Heating an alcoholic solution of sodium hydroxide and 1-bromopentane at 60C yields primarily: A) B) C) OH D) O E) Ans: D Topic: Predicting mechanisms.8 and 6.18 Difficulty Level: Medium 94) What would be the major product(s) of the following reaction? 40 . 8 and 6.18 Difficulty Level: Medium 95) What would be the major product(s) of the following reaction? CH3OH Br heat H3CO I II III IV A) I and II B) I. Ans: E Topic: Predicting products Section: 6. II. O CF3 S O NaN3 O DMF N3 N3 O I II III IV A) I B) II C) III D) IV E) None of these choices. II. and IV E) None of these choices. 41 . and III C) III D) I. 1.8 and 6. DMF O A) B) CN C) CN D) E) More than one of these choices Ans: C Topic: Synthesis.8 and 6. acetone O O S F3C 2. 1. reagent selection Sections: 6. CH3CO2Na. CH3CO2H A) B) O O 42 . NaI. NaCN.18 Difficulty Level: Medium 96) Predict the product(s) for the following reaction sequence.18 Difficulty Level: Medium 97) Predict the product(s) for the following reaction sequence. NaI. acetone Cl 2.Ans: D Topic: Predicting products Section: 6. 8 and 6. which is the major product? A) HSCH2CH2OCH2CH3 B) CH3CH2SCH2CH2OH C) CH3CH2SCH2CH2OCH2CH3 D) CH2=CH2 E) CH3CH3 Ans: B Topic: Predicting mechanisms.8 and 6. the major product is: A) CH3OCH2CH2CH2CH2Cl B) CH3OCH2CH2CH2CH2I C) CH3OCH2CH2CH2CH2OCH3 D) CH2=CHCH2CH2Cl E) CH2=CHCH2CH2I Ans: A Topic: Predicting mechanisms.18 Difficulty Level: Medium 98) When 0.C) O O D) E) A mixture of two of these choices Ans: C Topic: Synthesis. products Sections: 6. sequentially. products Sections: 6.10 mol of HSCH2CH2OH reacts at 25C. 0.10 mol of ICH2CH2CH2CH2Cl reacts with 0.10 mol of NaOCH3 in CH3OH at 40C.8 and 6. reagent selection Sections: 6.10 mol of CH3CH2Br followed by the addition of H2O. with 0.18 Difficulty Level: Medium 99) If 0.20 mol of NaH.18 Difficulty Level: Hard 43 . THF b.8 and 6. 1-iodopropane 44 . Ans: B Topic: Predicting mechanisms.8 and 6.18 Difficulty Level: Hard 102) Predict the product(s) for the following reaction sequence. NaH. products Sections: 6.18 Difficulty Level: Hard 101) The product(s) for the following reaction would mainly be dictated by which mechanism? Br CH3SNa EtOH A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. products Sections: 6. OH a.100) What would be the major product obtained when trans-1-bromo-3-methylcyclopentane is allowed to react with NaSH at 25oC? H3C H H3C SH H3C SH H3C H H SH H H H Br HS Br I II III IV A) I B) II C) III D) IV E) Equal amounts of I and II. Ans: B Topic: Predicting mechanisms. 13. O A) O B) I + OH C) + D) E) None of these choices.8. 6.+ RL Nu-R + L-. Ans: A Topic: Synthesis.) D) All of these choices.18 Difficulty Level: Easy 104) Which of the following statements is (are) true of an SN2 reaction of (R)-2-bromobutane with hydroxide ion? A) Doubling the hydroxide ion concentration would double the rate of the reaction. (Assume that all other experimental conditions are unchanged. C) by using a solvent of high polarity. reagent selection Sections: 6. (Assume that all other experimental conditions are unchanged. Ans: B Topic: Generalities Sections: 6. Nu. are favored A) when tertiary substrates are used. 6. B) by using a high concentration of the nucleophile. E) by none of these choices.) B) The major product would be (S)-2-butanol. C) Doubling the concentration of (R)-2-bromobutane would double the rate of the reaction.18 Difficulty Level: Medium 103) SN2 reactions of the type. 45 .8 and 6. D) by the use of weak nucleophiles. 6. due to competing elimination)? A) HO + CH3CH2CH2CHICH3 CH3 CH2CH2CHOHCH3 + I B) Cl + CH3CH2CH2CH2–OH CH3CH2CH2CH2–Cl + OH C) CH3S + CH3CH2CH2–OCH3 CH3S–CH2CH2CH3 + OCH3 D) All of these choices are likely to occur. 6.E) Two of these choices.18 Difficulty Level: Hard 46 . Ans: A Topic: Predicting products Sections: 6. 6. 6. Ans: B Topic: Predicting mechanisms.13. products Sections: 6.18 Difficulty Level: Medium 105) Which nucleophilic substitution reaction would be likely to occur (although probably not in excellent yield. Ans: D Topic: Generalities Sections: 6.13. E) None of these choices are likely to occur.8.18 Difficulty Level: Medium 106) The major product(s) for the following reaction would mainly be dictated by which mechanism? O CF3 S O NaN3 O CH3CH2OH A) SN1 B) SN2 C) E1 D) E2 E) None of these choices.8. 6.8.13. 6. Ans: E Topic: Predicting products 47 .107) What would be the major product(s) of the following reaction? Li Br THF I II III IV A) I B) II C) III D) IV E) More than one of these choices. 6. 6.14.8. Ans: A Topic: Predicting products Sections: 6.18 Difficulty Level: Medium 108) What would be the major product(s) of the following reaction? NaCN I DMSO C CN DMSO I II III IV A) I B) II C) III D) IV E) None of these choices. 8. reagent selection Sections: 6. 48 . 6.Section: 6.18 Difficulty Level: Medium 109) Predict the product(s) for the following reaction sequence. 6. EtOH A) B) C) D) E) None of these choices.14. EtOH Li A) B) Br C) D) E) None of these choices. Ans: C Topic: Synthesis. a.14. 1-bromobutane 2. H2 (excess). 6. H3C Li I b.18 Difficulty Level: Medium 110) Predict the product(s) for the following reaction sequence. Pd/C. H2 (excess). 1. Pd/C.8. THF. 6. 15 and 6. 6.Ans: E Topic: Synthesis. 6.18 Difficulty Level: Hard 111) What would be the major product(s) of the following reaction? t-BuOK Cl t-BuOH t-BuO I II III IV A) I B) II C) III D) IV E) More than one of these choices. Ans: D Topic: Predicting products Section: 6.18 Difficulty Level: Easy 112) What would be the major product(s) of the following reaction? O CH3CH2ONa O S O 60 oC OCH2CH3 I II III IV A) I and II B) II and III C) III and IV 49 .8.14. reagent selection Sections: 6. 18 Difficulty Level: Easy 113) Which of these compounds would give the largest E2/SN2 product ratio on reaction with sodium ethoxide in ethanol at 55°C? Cl A) B) Cl C) Cl D) Cl Cl E) Ans: D Topic: Predicting mechanisms Sections: 6.16 and 6. 6.16.8. Ans: D Topic: Predicting products Section: 6. 6.18 Difficulty Level: Medium 114) What would be the major product(s) of the following reaction? t-BuOK.D) I and IV E) All of these choices. t-BuOH Cl Ot-Bu I II III IV 50 . A) I B) II C) III D) IV E) More than one of these choices.18 Difficulty Level: Easy 116) The major product(s) for the following reaction would mainly be dictated by which mechanism? O CF3 S O CH3CH2OLi O CH3CH2OH A) SN1 B) SN2 C) E1 51 .16.18 Difficulty Level: Easy 115) The product(s) for the following reaction would mainly be dictated by which mechanism? t-BuOK t-BuOH Cl A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. Ans: A Topic: Predicting products Sections: 6. products Sections: 6.15. 6. 6.15.16. 6. Ans: D Topic: Predicting mechanisms. 6. D) E2 E) None of these choices. Ans: D Topic: Predicting mechanisms, products Sections: 6.15, 6.16, 6.18 Difficulty Level: Easy 117) What would be the major product(s) of the following reaction? EtOH, EtONa Cl EtO I II III IV A) I and III B) I and II C) II and III D) IV E) None of these choices. Ans: B Topic: Predicting products Sections: 6.15, 6.16, 6.18 Difficulty Level: Medium 118) What would be the major product(s) of the following reaction? 52 H3C CH3 CH3O/ CH3OH H Br 55oC H3C CH3 H3C OCH3 H OCH3 H CH3 I II H3C CH3 H3C III IV A) I B) II C) III and IV D) I and II E) All of these choices. Ans: C Topic: Predicting mechanisms, products Sections: 6.15, 6.16, 6.18 Difficulty Level: Medium 119) What would be the major product(s) of the following reaction? (CH3)2CHONa Cl (CH3)2CHOH 60 oC OCH(CH3)2 I II III IV A) I B) II, III, and IV C) III and IV D) II and IV E) IV and III 53 Ans: C Topic: Predicting products Sections: 6.15, 6.16, 6.18 Difficulty Level: Medium 120) The product(s) for the following reaction would mainly be dictated by which mechanism? EtOH, EtONa Cl A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. Ans: D Topic: Predicting mechanisms, products Sections: 6.15, 6.16, 6.18 Difficulty Level: Medium 121) Predict the major product(s) for the following reaction sequence. a. NaH, THF OH Br b. 60 oC O O A) A mixture of and O B) 54 C) D) E) A mixture of two of these choices. Ans: E Topic: Synthesis, reagent selection Sections: 6.15, 6.16, 6.18 Difficulty Level: Hard 122) Predict the product(s) for the following reaction sequence. 1. t-BuOK, t-BuOH Br 2. H2, Pd/C, EtOH A) B) Ot-Bu C) D) E) None of these choices. Ans: A Topic: Synthesis, reagent selection Sections: 6.15, 6.16, 6.18 Difficulty Level: Hard 123) Treating (CH3)3C-Cl with a mixture of H2O and CH3OH at room temperature would yield: A) CH2=C(CH3)2 B) (CH3)3COH C) (CH3)3COCH3 D) All of these choices. 55 products Section: 6.18 Difficulty Level: Medium 124) Treating 1-bromo-1-methylcyclohexane with CH3OH at room temperature would yield: OCH3 A) B) C) D) All of these choices. E) None of these choices. Ans: D Topic: Predicting mechanisms. products Section: 6.18 Difficulty Level: Medium 125) Which would be formed in the following reaction? CH3 CH3OH H3C Br ? o 55 C H OCH3 CH3 H3C CH3 H3C OCH3 H H I II CH3 CH3 CH3 CH2 III IV 56 . Ans: D Topic: Predicting mechanisms.E) None of these choices. 18 Difficulty Level: Medium 126) What would be the major product(s) of the following reaction? Br EtOH 20 oC OEt EtO I II III IV A) I and II B) II and III C) I and III D) IV E) None of these choices.18 Difficulty Level: Medium 127) What would be the major product(s) of the following reaction? 57 . Ans: E Topic: Predicting mechanisms.A) I B) II C) III D) IV E) All of these choices.12 and 6. products Section: 6. Ans: C Topic: Predicting products Section: 6. II. Ans: A Topic: Predicting products Sections: 6.18 Difficulty Level: Medium 58 .12 and 6. Ans: D Topic: Predicting products Section: 6. CH3 CH3CH2CO2H Br CH3 CH3 room temperature O O O O I II III IV A) I B) II C) III D) IV E) None of these choices.12 and 6.18 Difficulty Level: Medium 128) What would be the major product(s) of the following reaction? HO Br 20 oC (CH3)2CHCH2O (CH3)2CHCH2O (CH3)2CHCH2O I II III IV A) I and II B) I. and III C) III D) IV E) None of these choices. C) SN1 reactions of alkyl halides are favored by polar solvents. products Sections: 6. and SN1 reactions of alkyl halides are favored by polar solvents.18 Difficulty Level: Easy 131) Which of the following statements is (are) true of SN1 reactions of alkyl halides in general? A) The rate of an SN1 reaction depends on the concentration of the alkyl halide. there is/are formed: A) OH B) OC2H5 C) D) E) All of these choices. B) The rate of an SN1 reaction depends on the concentration of the nucleophile. 6. Ans: E Topic: Predicting mechanisms.18 Difficulty Level: Medium 130) Which of the following statements is (are) true of SN1 reactions of alkyl halides in general? A) The rate of an SN1 reaction depends on the concentration of the alkyl halide. D) The rate of an SN1 reaction depends on the concentration of the alkyl halide and SN1 reactions of alkyl halides are favored by polar solvents.129) When tert-pentyl chloride undergoes solvolysis in aqueous ethanol at room temperature. B) The rate of an SN1 reaction depends on the concentration of the nucleophile. 6.12 and 6. E) The rate of an SN1 reaction depends on the concentration of the alkyl halide and the concentration of the nucleophile. 59 . Ans: D Topic: Generalities Sections: 6.13.12. 18 Difficulty Level: Easy 133) SN1 reactions of the following type: Nu:.12. Ans: A Topic: Generalities Sections: 6. 6. E) by more than one of these choices.12. 6. C) by increasing the polarity of the solvent. D) by use of a non-polar solvent.12.C) SN1 reactions of alkyl halides occur faster in polar aprotic solvents (compared to protic solvents). D) by use of a strong base.+ RL Nu–R + L-. Ans: A Topic: Generalities Sections: 6. Nu. B) by increasing the concentration of the nucleophile.13. are favored A) when tertiary substrates are used. 6.18 60 . and SN1 reactions of alkyl halides occur faster in polar aprotic solvents (compared to protic solvents).+ R-X R-Nu + :X- are favored A) by the use of tertiary substrates (as opposed to primary or secondary substrates). E) by none of these choices. 6.13. 6. C) when L. B) by using a high concentration of the nucleophile.18 Difficulty Level: Easy 132) SN1 reactions of the type.is a strong base. D) The rate of an SN1 reaction depends on the concentration of the alkyl halide and SN1 reactions of alkyl halides occur faster in polar aprotic solvents (compared to protic solvents).13. Ans: A Topic: Generalities Sections: 6. 6. E) The rate of an SN1 reaction depends on the concentration of the alkyl halide and the concentration of the nucleophile. B) by increasing the concentration of the nucleophile. Ans: E Topic: Generalities Sections: 6.13.12.18 Difficulty Level: Hard 135) What would be the major product(s) of the following reaction? CH3CH2OH Br 25 oC OCH2CH3 OCH2CH3 I II III IV A) I B) II C) III D) IV E) None of these choices. E) by the use of tertiary substrates (as opposed to primary or secondary substrates) and by use of a weak nucleophile.Difficulty Level: Medium 134) SN1 reactions of the following type: Nu:.12.18 Difficulty Level: Medium 61 . 6. 6. Ans: E Topic: Predicting products Section: 6. 6. C) by increasing the polarity of the solvent.+ R-X R-Nu + :X- are favored A) by the use of tertiary substrates (as opposed to primary or secondary substrates).14. 6. D) by use of a weak nucleophile. Ans: A Topic: Predicting mechanisms.136) The product(s) for the following reaction would mainly be dictated by which mechanism? A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. 6.14. 6. Ans: E Topic: Predicting products Sections: 6. 6.18 Difficulty Level: Easy 137) What would be the major product(s) of the following reaction? (CH3)2CHOH Br 70 oC OCH(CH3)2 OCH(CH3)2 I II III IV A) I B) II C) III D) IV E) None of these choices. products Sections: 6.17. 6.17. 6.18 62 .15.12. 15.Difficulty Level: Easy 138) What would be the major product(s) of the following reaction? CH3OH Br OCH3 I II III IV A) I B) II C) III D) IV E) None of these choices.17. 6. products Sections: 6. 6. 6. Ans: C Topic: Predicting mechanisms.18 Difficulty Level: Easy 139) The product(s) for the following reaction would mainly be dictated by which mechanism? 1-pentanol 80 oC Cl A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. 6.18 Difficulty Level: Easy 63 .15.17. Ans: E Topic: Predicting products Sections: 6. 17.15. 6.140) The product(s) for the following reaction would mainly be dictated by which mechanism? O CF3 S O CH3CH2OH O 60 oC A) SN1 B) SN2 C) E1 D) E2 E) None of these choices. Ans: C Topic: Predicting mechanisms. 6. products Sections: 6. Ans: E Topic: Predicting products 64 .18 Difficulty Level: Easy 141) What would be the major product(s) of the following reaction? HO Br 80 oC (CH3)2CHCH2O I II III IV A) I B) II C) III D) IV E) More than one of these choices. 6.17. Ans: E 65 .Sections: 6. heat Cl Ot-Bu I II III IV A) I B) II C) III D) IV E) None of these choices. Ans: D Topic: Predicting products Sections: 6. 6.15. 6.18 Difficulty Level: Medium 143) What would be the major product(s) of the following reaction? t-BuOH. 6.17. III.18 Difficulty Level: Medium 142) What would be the major product(s) of the following reaction? Cl (CH3)2CHOH 70 oC OCH(CH3)2 I II III IV A) I B) II and III C) II.15. and IV D) III and IV E) None of these choices. EtOH.18 Difficulty Level: Medium 144) The product(s) for the following reaction would mainly be dictated by which mechanism? A) SN1 B) SN2 C) E1 D) E2 E) None of these choices.Topic: Predicting products Sections: 6. 6.15. 6. 1. H2. Ans: D 66 . products Sections: 6. Ans: A Topic: Predicting mechanisms.17. 6. Pd/C. EtOH EtO A) EtO B) C) D) E) A mixture of two of these choices.17. heat Br 2. 6.15.18 Difficulty Level: Medium 145) Predict the product(s) for the following reaction sequence. 18 Difficulty Level: Medium 146) Which would be the major product of the following reaction? CH3 H (CH3)3CO ? (CH3)3COH H Cl 55oC CH3 OC(CH3)3 CH3 H H3C H3C H I H OC(CH3)3 I II III IV A) I B) II C) III D) IV E) None of these choices.Topic: Synthesis. products Section: 6. 6.18 Difficulty Level: Easy 147) The product(s) for the following reaction would mainly be dictated by which mechanism? A) SN1 B) SN2 C) E1 67 .17.15. 6. reagent selection Sections: 6. Ans: C Topic: Predicting mechanisms. 17. products Sections: 6.12 and 6.15.18 Difficulty Level: Hard 148) The product(s) for the following reaction would mainly be dictated by which mechanism? Br EtOH heat A) SN1 B) SN2 C) E1 D) E2 E) None of these choices.18 Difficulty Level: Hard 149) Which would be formed in the following reaction? 68 . products Sections: 6. 6.D) E2 E) None of these choices. Ans: C Topic: Predicting mechanisms. 6. Ans: A Topic: Predicting mechanisms. Br 1.18 Difficulty Level: Hard 150) Predict the major product(s) for the following reaction sequence. products Section: 6. 20 oC OH A) OH B) C) 69 . NaI. CH3 O Br OH H3 C ? o 50 C H O CH3 O O H3C O H3C CH3 H H I II III IV A) I B) II C) III D) IV E) All of these choices. H2O. acetone 2. Ans: E Topic: Predicting mechanisms. 0 M NaOH in a mixture of water and methanol would yield mainly 70 . 6. Predict the product(s) for the following reaction sequence. reagent selection Sections: 6.8. reagent selection Sections: 6.D) E) A 1:1 mixture of two of these choices.15.16. OH A) OD B) C) Na D) E) None of these choices. 6. ) Ans: E Topic: Synthesis.12 Difficulty Level: Hard 151. Ans: B Topic: Synthesis.18 Difficulty Level: Hard 152) Heating tert-butyl chloride with 1. 6.18 then 6. Ans: E Topic: Predicting mechanism.A) (CH3)3COH through an SN1 reaction. D) (CH3)3COCH3 through an SN2 reaction. E) CH2=C(CH3)2 through an E2 reaction. Ans: True Topic: Free energy diagrams Sections: 6.10 Difficulty Level: Hard 154) An endergonic SN2 reaction will have a have a higher energy of activation (G‡) than an exergonic SN2 reaction.7 Difficulty Level: Medium 71 . Ans: False Topic: Hammond Postulate Sections: 6. products Sections: 6. B) (CH3)3COCH3 through an SN1 reaction.7 and 6. Ans: False Topic: Temperature and rate Section: 6.8 Difficulty Level: Medium 155) Increasing the temperature of a reaction will speed up the overall rate as this will increase the energy of activation for reaction. C) (CH3)3COH through an SN2 reaction.18 Difficulty Level: Hard Question type: True/false 153) In a highly exergonic SN2 reaction we can assume the transition state is similar to the products formed in the reaction.7 and 6. the size of the halogen atom increases. they must ___ and ___. weaker Topic: Bond length.12 Difficulty Level: Medium 157) All SN1 reactions will always be accompanied by a competing E1 reaction. Ans: transition state Topic: Transition state theory Section: 6.156) Racemic mixtures form in SN1 reactions when leaving group departure results in a loss of chirality followed by subsequent attack of the nucleophile.6 Difficulty Level: Easy 160) In order for colliding species to react. approach with the proper orientation.4 Difficulty Level: Easy 159) In the SN2 reaction. the carbon-halogen bond length gets ___ and the bond strength gets ___. Ans: False Topic: E1 reactions Section: 6. Ans: have energy equal/greater than the activation energy. leaving groups Section: 6. bond strength. Ans: True Topic: SN1 stereochemistry Section: 6. 72 . Ans: longer. accordingly. the unstable arrangement of atoms in which both the nucleophile and the leaving group are partially bonded to the same carbon atom is called the ___.17 Difficulty Level: Medium Question type: text-entry 158) As we go down Group 7A of the periodic table. where the methanol oxygen acts as a nucleophile. SN2 Sections: 6. 73 . Propose a likely structure for this product. Ans: The reaction is likely to occur via an SN1 mechanism.. leading to the formation of a tertiary carbocation. Ans: The alcohol is likely to be first deprotonated by the strong base. which can then undergo intramolecular SN2 reaction to afford the observed product.. generating an alkoxide ion. Cl . suggesting a reasonable mechanistic pathway for its formation.Topic: Activation energy. transition state theory Section: 6.8 Difficulty Level: Hard 163) Draw the potential energy diagram that represents an exothermic reaction between a tertiary alkyl halide and methanol. attaching to the positively charged carbon. The first step is the rate-determining step. : Na O NaCl H2 Topic: Acid-base reactions. the product is analyzed to be C5H10O. Briefly explain your rationale..7 Difficulty Level: Medium 161) What final product is likely to be obtained through the following series of reactions? OH NaH Cl A B diethylether O Ans: Topic: Multistep synthesis.8 Difficulty Level: Medium 162) When 5-bromo-1-pentanol is treated with sodium hydride in diethyl ether. forming a protonated ether. The second step is a fast step. a cyclic ether. NaH . . acid-base reactions. the last step is a fast loss of a proton to form the (uncharged) ether product. + O Cl OH .. intramolecular SN2 Sections: 6. 7 and 6. Ans: An SN1 reaction is a multi-step process. Ans: hyperconjugation Topic: Carbocation stability Section: 6.12 Difficulty Level: Easy 74 . Since the nucleophile is not involved in the rate- determining step. changes in its concentration typically have no impact on the rate of reaction. the overall reaction rate is determined by the rate of formation of the carbocation intermediate. The reason for this is that ___.11 Difficulty Level: Medium 166) Typically. Topic: SN1 kinetics Section: 6.6 Difficulty Level: Medium 165) The stabilizing effect of alkyl substituents on carbocations can be explained through ___.10 Difficulty Level: Hard 164) A nucleophile in an SN2 reaction must approach from the ___ of the carbon atom attached to the leaving group since the electrons in the nucleophile’s HOMO begins to overlap with the ___ of the carbon atom attached to the leaving group. Ans: backside and LUMO Topic: SN2 mechanism Section 6. increasing the concentration of the nucleophile of an SN1 reaction has no impact on the rate of the reaction.Energy time Topic: Free energy diagrams Sections: 6. 12 Difficulty Level: Easy 169) A student has isolated a chiral alkyl halide (shown below) with a specific rotation of [] = +22. Suggest a mechanism to justify these results. Ans: SN1 Topic: Carbocation stability Sections: 6.12 Difficulty Level: Easy 168) A reaction in which the nucleophile is a molecule of the solvent is referred to as a ___ reaction. However.167) The substitution mechanism whose rate depends primarily on the relative stability of the intermediate carbocation is the ___. Ans: solvolysis Topic: Solvolysis Section: 6. following the addition of the MeOH and loss of a proton a racemic mixture is formed which gives a [] = 0o.11 and 6.1o. reanalysis of the alkyl halide showed a new chemical formula of C11H16O with a specific rotation of [] = 0o. The student decided to store the compound in the solvent MeOH overnight. 75 . Ans: In leaving the compound in MeOH a solvolysis reaction has occurred which results in carbocation formation. Ans: The iodide ion will attack the alkyl chloride producing alkyl iodides which are more reactive due to the better iodide leaving group and will allow for ether formation. where the nucleophile is essentially unsolvated. thus. Explain.13 Difficulty Level: Medium 171) Increasing the concentration of either of the reactants of an SN2 reaction increases the rate of the reaction. Topic: Nucleophilicity.13 Difficulty Level: Hard 172) The relative nucleophilicity of the halide ions in polar aprotic solvents is observed to be markedly different from that in protic solvents. The iodide ion 76 . Explain briefly. less electronegative and more polarizable iodide ion.3 and 6.13 Difficulty Level: Hard 173) Typically alkyl chlorides are slow in SN2 reactions with sodium methoxide in methanol. Ans: The smaller. solvent effects Sections: 6. The primary reason for this is that increasing the concentration increases ___. the nucleophilicity parallels the basicity of the halide ions. Ans: the frequency of collisions between reactant species. The situation is reversed in aprotic solvents.12 Difficulty Level: Medium 170) The substitution mechanism whose rate depends primarily on the degree of steric hindrance around the leaving group is the ___. kinetics Sections: 6. Ans: SN2 Topic: Steric hindrance Section: 6.Topic: Solvolysis Sectioin: 6. so that the fluoride ion is the strongest nucleophile of the halide ions.7 and 6. however the rate of the reaction can be greatly increased with a small addition of NaI. more highly electronegative fluoride ion is more effectively solvated in a protic solvent and is therefore a weaker nucleophile compared to the larger. thereby statistically increasing the chance encounters between species having the requisite Eactivation Topic: Activation energy. leading to the formation of a tertiary carbocation.3 and 6.14 Difficulty Level: Medium 175) What final product is likely to be obtained through the following series of reactions? NaNH2 Cl excess H2 A B C NH3(l) Ni Ans: Topic: Multistep synthesis. Ans: The reaction is likely to occur via an E1 mechanism. The first step is the rate-determining step. R-Cl + I.14. SN2 Sections: 6. hydrogenation Sections: 6. 4.16 Difficulty Level: Hard 176) Give a detailed reaction mechanism for the reaction expected to occur when 2-bromo-2- methylpentane is heated with methanol.13 Difficulty Level: Hard 174) What final product is likely to be obtained through the following series of reactions? NaNH2 Br A B NH3(l) Ans: Topic: Multistep synthesis. Also indicate which step is likely to be rate- determining.+ R-I + MeO. and thus only a small quantity is needed. R-OMe + I- Topic: Nucleophilicity.is regenerated at the end of the reaction making it a catalyst. followed by base promoted elimination to afford 2 different alkene products. SN2. Cl. 77 . Draw clear structural formulas of all relevant species and use curved arrows to represent electron flow. solvent effects Sections: 6. acid-base reactions. acid-base reactions. 78 . . one of the isomers react 500 times faster than the other one. [ . 6. In addition. this hydrogen has significant steric hindrance caused by the isopropyl group meaning compound I’s reaction will be slow. Determine the products of each isomer and explain your reasoning. one isomer gives only A as a product and the other isomer gives a mixture of A and B as products. : Br : H . Ans: By looking at the chair conformations of I and II with the leaving group axial we can see that compound I can only produce B with a hydrogen in anti-perplaner conformation. 6..16.. ] H Topic: Predicting reaction mechanisms Sections: 6. Compound II lacks this steric hindrance and can give 2 possible products as it has 2 hydrogens that can eliminate anti to the Br.. Also.. 3 . slow HOCH ..:Br: fast .15.17 Difficulty Level: Medium 177) When diastereomers I and II undergo an E2 elimination on treatment with sodium ethoxide in ethanol. 16. 6. E2 is the major mechanism dominating the reaction. 6. Ans: Notice that an SN2 reaction is not likely due to sterics of approaching the leaving group Cl from the backside as well as running this reaction in a polar protic solvent. Explain why.15. SN1/E1 reaction also seem unlikely as a secondary alkyl halide will not form a very stable carbocation without rearrangement. 79 .Topic: Predicting reaction mechanisms Sections: 6. only one major product is observed in the reaction below. and to be sensitive to its mechanistic requirements.17 Difficulty Level: Hard 178) Even though sodium ethoxide is a strong nucleophile and a strong base. we must have the Cl leaving group anit-periplaner to the incoming nucleophile. Topic: Predicting reaction mechanisms Sections: 6.16. 6.17 Difficulty Level: Medium 80 .15. 6.