C201CR2F05RichsReview

C201CR2F05RichsReview - MPRE .CO 411 MED MPRE .CO 411 What...

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Unformatted text preview: MPRE .CO 411 MED MPRE .CO 411 What is the molecular formula of this structure? Use DOU. O O MED 6. MPRE .CO 411 MED 411 MPRE .CO 411 MED - PR E OM 1.C D41 411 - PR EME MED OM T1S00-16[4] 1.C D41 MPRE ME .CO 411 MED PRE 411 .CO .CO 411 MED 411 MED MPRE .CO 411 MED .CO MPRE T1S97-02[5] Radical chain reactions tend to be associated with: [1] the creation and propagation of cations [2] the creation and propagation of anions [3] hydrolysis [4] homolytic bond cleavage [5] the use of large amounts of catalyst 9. MPRE T1S99-12[5] 411 MPRE .CO 411 MED MPRE MED MPRE T1S97-09[1] What is the net charge, hybridization, and shape of the structure shown. All valance H electrons are displayed. [1] zero, sp‹, trigonal planar [2] zero, sp¤, trigonal pyramidal [3] +1, sp‹, trigonal planar [4] +1, sp¤ trigonal pyramidal [5] +1, sp¤, trigonal planar 8. .CO PRE MED 411 .CO MPRE MED 3. T1S01-09[1] For the previous diagram, which is the activation energy for the overall reaction in the reverse direction? [1] D minus E [2] B minus E [3] B minus D [4] B minus E [5] A minus E MED 411 MED MPRE 411 .CO T1S00-16[03] How many sigma and pi bonds, respectively, are present in (CH‰CH„)„CÙC(CH‰)Cl [1] 20, 1 [2] 21, 1 [3] 21, 2 [4] 22, 2 [5] 23, 2 7. .CO T1S01-09[4] ANSWERS IN BRACKETS 2. Which statement is false with regard to the previous diagram? [1] The transition from energy level E to energy level B represents the overall energy of activation of the reverse reaction. [2] The energy of reaction is negative. [3] The transition from energy level D to energy level C, represents the the energy change between the reactants and the intermediate. [4] The magnitude of the energy barrier that most be over come is of greater importance when evaluating the rate of reaction, than is the absolute value of the most energetic activated complex present in the reaction mechanism. [5] If the intermediate in this reaction mechanism were produced by some alternative pathway, the product of this reaction would form faster than the reactant would. MPRE MED MPRE [1] CŒŒHŒÁO„ [2] CŒŒHŒËO„ [3] CŒŒHŒÈO„ [4] CŒŒHŒØO„ .CO Which statement is FALSE with regard to this diagram? [1] The reaction has two steps the first is endothermic, while the second is exothermic. [2] The first step is the rate determining step [3] Two transition states are present in the reaction mechanism [4] At equilibrium the concentration of the intermediate will be greater than the reactant. [5] At equilibrium the concentration of the products will exceed the concentration of the reactants. .CO MED MPRE .CO MED 411 - PR EM COM 11. ED4 - PR EM COM 11. ED4 - PR EM T1S980405-[1] COM 11. OH Z T1S99-01[3] ANSWERS IN BRACKETS What is the expected bond angle between atoms X and Y, and between atoms Y and Z, respectively, in the representation above? [1] 180Î, 120Î [2] 180, 180Î [3] 109.5Î, 120Î [4] 109Î, 180Î [5] 109, 109Î 5. MPRE M ED4 C .CO Energy C Y [1] 1,3,2 [2] 2,3,1 [3] 2,2,2 [4] 3,2,1 [5] 3,1,2 1. The next two questions pertains to this energy A B C D E Reaction Progress C 411 ED4 11. COM CH3 X MPRE O Rich Hochstim (305) 279-7660 Tutoring in the Sciences since 1984 diagram: MED - PR EM ED4 P These questions cover Chapters 3-6 in Bruice. Average time per question: 2 minutes. M 411 11. C201CR2F05 .CO COM © 2001 Richard Hochstim. All rights reserved. 4. What are the number of sp, sp¤ and sp‹ hybridized atoms respectively, in the compound below? H C H .CO [4] MED MPRE .CO 2 411 - PR EM COM 11. T1S98-02[3] 16. Indicate the E, Z configuration for the double bonds labeled 1 and 2, respectively. .CO 411 MPRE .CO COM 411 11. MED [1] addition and elimination [2] addition and substitution [3] addition and rearrangement [4] substitution and rearrangement [5] elimination and substitution 411 .CO MED MPRE .CO 411 MED MPRE .CO 411 MED - PR E MED D41 - PR EME OM 1.C 411 .CO MPRE ME D41 T1S99-18[3] MED Reaction progress ---> PRE .CO 1.C OM MPRE .CO [4] T2S01-02[2] MP RE Energy --->MED411 411 MED MPRE .CO 411 MED PRE MPRE .CO 411 .CO 411 MED MPRE .CO T2S01-01[4] 19. Which compound can exhibit cis/trans isomerism? [1] CH‰CH„(CH‰)CÙC(CH‰)„ [2] CH‰CH„(CH‰)CÙC(CH‰)CH„CH‰ [3] CH‰CH„(CH‰)CÙCH„ [4] (CH‰CH„)„CÙC(CH‰)CH„CH‰ [2] [3} Reaction Progress [1] A, C [2] B, C [3] B, D [4] C, D [5] A, B [5] [1] [5] T1S00-22[1] 18. Which of the following reagents will react with propene? [A] NaOH [B] KI/H„O [C] KI/H‰PO [D] HI 411 MED MPRE 411 .CO T1S001-22[1] 14. Which reaction energy profile best represents a “fast endothermic reaction”? MED 411 MED [4] MPRE T2S98-14[3] 13. Which of the following determines the value of the equilibrium constant for a reaction? [1] The free energy difference between the products and reactants. [2] The energy of activation of the slow step [3] The energy of activation of the overall reaction [4] The free energy difference between the products and highest energy transition state. [5]The absolute entropy of the highest energy transition state. [3] MPRE [2] .CO MPRE [1] MED 411 .CO Energy MPRE MED ED4 MPRE M Cl 411 .CO Cl 1 T2S01-18[3] 17. Which energy profile most closely reflects the changes in energy which occur when 2-methylpropene undergoes electrophillic addition of HBr to produce tert-butyl bromide? T1S96-18[4] 12. Which type of reaction is depicted below? HCl Cl Cl Cl MED 11. ED4 - PR EM [1] Elimination [2] Substitution [3] Addition [4] Rearrangement MPRE [1] E,E [2] Z,Z [3] E,Z [4] Z,E [5] This ain’t so E,Z! COM H± MED - PR EM ED4 T1S96-17[3] 11. Which type of reaction is depicted below? Cl 411 11. [3] ED4 [1] Elimination [2] Substitution [3] Addition [4] Rearrangement [1] Cl [2] COM Cl MPRE - PR EM MED ED4 411 11. .CO COM M © 2001 Richard Hochstim. All rights reserved. 10. Which type of reaction is depicted below? 15. Phosgene is a toxic gas that has an odor like fresh straw. Its chemical formula is CCl„O. Which is the correct Lewis dot O structure of phosgene? O OCH 3 Cl heat Cl Cl Cl C O Cl + CO CO CO OCH 3 C(CH3)CH2CH3 411 411 .CO .CO MPRE MPRE M MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM M © 2001 Richard Hochstim. All rights reserved. 20. Hi, can you deduce my IUPAC name? 24. When HCl attacks isobutene (2-methylpropene) via [1] cis-4-ethyl-1,2-dimethylcyclohexene Markovnikov addition which of the following is NOT true? [2] cis- 6-ethyl-3,4[1] the first step involves a proton and the π bond of the dimethylcyclohexene alkene, [3] cis-3-ethyl-5,6-dimethylcyclohexene [2] this is a two step reaction and the first step is rate [4] cis-3,4,6,6-tetramethylcyclohexene determining. [5] cis-3,3,5,6-tetramethylcyclohexene [3] the intermediate is the isobutyl cation. [6] cis-Rumplstiltskene [4] the chloride ion attacks the intermediatein the second step. T2S01-03[5] [5] overall reaction is exothermic 21. The “E,Z system” of nomenclature assigns the priorities of atoms/groups attached to carbon-carbon double bonds T2S01-16[3] based on: 25. Which of the following statements will not always be true? [1] atomic number [2] mass number [3] formula weight [1] For a reaction with more than one step, the energy [4] Hammond’s postulate [5] Markovnikov’s rule difference between the most energetic transition state and the reactants is the overall energy of activation of the Me[1] reaction. 22. Which of the alkenes below has the Z configuration? [2] The activation energy for any given step in a mechanism is the difference between the energy of the transition state Cl H 2N CN in that step and the energy of the starting materials in that step. [3] The difference in energy between the products and reactants under conditions of constant pressure is known as [1] [2] the enthalpy of reaction. [4] The step with the most energetic transition state will be the rate determining step. [5] At equilibrium the rate of the forward and reverse HO H 2NCH2 CN reaction will be the same. 411 MED MPRE 411 MED MED MPRE .CO 411 MED - PR E C OM 1.C H 2NCH2CH2CH2 CH2CH2CN D41 CH2CH3 [4] T2S98-1920[3] 27. How many π and ø bonds are found in propene, respectively? [1] 1, 6 [2] 1, 8 [3] 1, 9 [4] 2, 6 [5] 2, 8 - PR EME C OM C D41 411 .CO T2S01-05[1] CH2CH2CN C 1.C MPRE MED 411 CH3(CH2)2 MPRE ME MED T1S98-12[2] PRE MED 411 .CO MPRE .CO 411 MED PRE E Reaction Coordinate MPRE MED MPRE .CO [3] D [1] At equilibrium the concentration of the the intermediate will be greater than the reactants but less than the products/ [2] Energy level C minus E represents the heat of reaction for the overall reaction in the reverse direction. [3] The energy of activation of the second step is represented by energy level A minus D. [4] Both steps in this energy profile are exothermic [5] The rate of this reaction is best determined by the magnitude of its “energy barrier”. .CO 411 (CH2)2CH(CH3)2 H 2NCH2CH2 CH3(CH2)4 C 411 .CO .CO T2S01-05[1] 23. Which of the alkenes below has the Z configuration? CH2CH3 ClCH2CH2 (CH3)2CH (CH2)3CH3 C C [1] [2] C C HOCH 2CH2 CH2C(CH3)3 CH3OCH 2CH2 CH2CH2Cl A B MPRE .CO 411 .CO 411 MED Cl MPRE CH3O MED [4] MPRE [3] Energy Level MED 411 .CO .CO MPRE MPRE MED MED T2S01-20[4] 26. Which of the following is incorrect regarding the following energy profile? MED 411 .CO Me[1] PRE PRE MED 411 .CO MPRE MPRE ME MED D41 411 1.C .CO OM MPRE - PR EME MED D41 411 1.C .CO OM MPRE - PR E MED MED 411 411 .CO .CO MPRE MPRE MED MED 411 411 .CO .CO MPRE MPRE MED MED 411 411 .CO .CO MPRE MPRE MED MED 411 411 .CO .CO MPRE MPRE MED MED 411 411 .CO .CO MPRE MPRE M MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM M © 2001 Richard Hochstim. All rights reserved. 33. Which of the following best explains the underlying reason 28. Indicate the correct hybridization of all atoms (except H) why Markovnikov’s rule is so frequently obeyed? below from left to right, respectively. [1] because Markovnikov’s rule is regiospecific. [1] sp‹, sp¤, sp, sp¤ [2] because protonation of the less substituted carbon is [2] sp‹, sp¤, sp, sp‹ sterically more favorable. [3] sp‹, sp¤, sp, sp CH3 N C O [3] because carbocation rearrangement leads to a more [4] sp¤, sp¤, sp¤, sp¤ stable intermediate. [5] sp¤, sp¤, sp, sp¤ [4] because Markovnikov addition leads to the production of the more stable carbocation. T1S98-15[1] [5] There are stiff fines for all compounds that disobey 29. A carbon atom hybridizes to become an sp¤. How many of Markovnikov’s rule. itsp orbitals remain unhybridized? [1] What a silly questionÇnone T2S00-14[4] [2] What a stupid questionÇone! 34. In a two step mechanism, the first step is endothermic and [3]What a dumb questionÇtwo! the second is exothermic. Which of the following will be [4] What a mind numbing questionÇthree true according to Hammond’s Postulate? [5] What an excellent questionÇit depends on stuff I don’t [1] The first transition state formed will most resemble the get! reactants. [2] The second transition state formed will most resemble Me[2] the intermediate 30. Retinal is also known as “visual purple”, its structure is [3] The overall reaction will be endothermic. shown below. What is its molecular formula? Note: DOU [4] The overall reaction will be exothermic. works the same if O is presentÃRich CH3 H 3C CH3 T2S00-15[2] 35. Which of the following are false? [1] A carbocation rearrangement is more likely if the initially formed carbocation is short-lived. CH3 CH3 [2] Rearrangements of tertiary carbocations is rarely CHO abserved. [1] C„∏H„ÈO [3] Rearrangements of methyl carbocations are never [2] C„∏H‰∏O observed. [3] C„∏H‰„O [4] 3,3-dimethyl-1-butene would be expected to rearrange [4] CŒÈH„ÈO when treated with HCl. [5] CŒÈH‰∏) [5] 2-methylpropene would be expected to rearrange when treated with HCl. T1S97-06[1] 31. Place the alkenes listed below in order of decreasing T2S00-20[5] B stability. 36. List the carbon-carbon bonds in A = 1-pentene B = trans-2-pentene C = (Z)-2-pentene propene in order of increasing D = 2-methyl-2 butene E = 2,3-dimethylbutene bond length. [1] A,B,C,D,E [2] E,D,C,B,A [3] A,C,B,D,E [4] [1] A>B>C [2] C>B>A E,D,B,C,A [5] D,A,B,C,E [3] B>A>C [4] C>B>A [5] C>C>A A C T2S00-13[4] 32. Place the alkenes listed below in order of increasing heat of T2S96-16[1] hydrogenation. 37. Say my name, say my name. A = 1-pentene B = trans-2-pentene C = (Z)-2-pentene D = 2-methyl-2 butene E = 2,3-dimethylbutene [1] A,B,C,D,E [2] E,D,C,B,A [3] A,C,B,D,E [4] E,D,B,C,A [5] D,A,B,C,E [1] (3E, 5Z)-3,6-dimethyl-3,5-nonadiene 38. T2S99-08[4] [2] (3Z, 5E)-3,6-dimethyl-3,5-nonadiene [3] (3E, 5E)-3,6-dimethyl-3,5-nonadiene [4] (3Z, 5Z)-3,5-dimethyl-3,5-nonadiene [5] (3E, 5Z)-3,5-dimethyl-3,5-nonadiene H H H 411 M .CO 411 H H H .CO 411 411 411 Br H H H H H H [4] [5] Br MPRE MED [2] Br .CO MPRE MED 411 .CO [3] 48. When Br„/H„O is used to react with an alkene, the product is a bromohydrin. What is the nucleophile which attacks in the second step of this reaction? [1] Br± [2] Br— [3] OH— [4] H„O [5] BrOH - PR E MED 411 [4] 49. Which of the following can act as an electrophile” [1] (CH‰)‰NH [2] C„HÁ [3] Br— [4] BF‰ [5] C„H - PR EME D41 1.C OM [4] 50. What is the expected product when Cl„ is added to 1methylcyclopentene? Cl H Cl Cl CH3 CH3 CH3 CH3 OM MED 411 .CO MPRE MED 411 .CO MPRE MED [3] 1.C D41 411 MPRE ME MED PRE MED 411 .CO MPRE .CO 411 MED PRE T2S00-20[5] .CO HH HH H .CO MPRE MED 411 .CO MPRE T2S00-14[4] 44. Which of the following are false? [1] A carbocation rearrangement is more likely if the initially formed carbocation is short-lived. [2] Rearrangements of tertiary carbocations is rarely abserved. [3] Rearrangements of methyl carbocations are never observed. [4] 3,3-dimethyl-1-butene would be expected to rearrange when treated with HCl. [5] 2-methylpropene would be expected to rearrange when treated with HCl. MED MED MPRE H .CO Me[2] 43. Which of the following best explains the underlying reason why Markovnikov’s rule is so frequently obeyed? [1] because Markovnikov’s rule is regiospecific. [2] because protonation of the less substituted carbon is sterically more favorable. [3] because carbocation rearrangement leads to a more stable intermediate. [4] because Markovnikov addition leads to the production of the more stable carbocation. [5] There are stiff fines for all compounds that disobey Markovnikov’s rule. [1] Br MPRE 411 .CO H Br H MPRE MPRE reaction progress [1] This reaction has an equilibrium constant equal to, or close to, one. [2] The first step is rate determining. [3] The first step is endergonic [4] The second step is excergonic MED MED 411 Br .CO MPRE structure of the intermediate in this same said reaction, as envisioned by 21st century scientists? .CO free energy MPRE M MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 11. COM © 2001 Richard Hochstim. All rights reserved. 45. Which of the following will reaction with an alkene? 39. Which of the following is not true? A = NaCl B = NaOH C = NaCl, H‰O± [1] hetrolytic bond cleavage forms ions [2] homolytic bond cleavage forms radicals D = KI E = KI, H„SO (trace) [3] the difference in energy between the products and [1] A,B [2] A,C [3] B,C [4] C,D [5] C,E reactants determine the equilibrium constant. [4] The rate of a reaction is determined by the height of the [5] “energy barrier”. 46. To convert 1-methylcyclohexene to trans-1-hydroxyl-2[5] A reaction with large positive ∆GÎ will have an methylcyclohexane use: equilibrium constant close to one. [1] hybroboration oxidation [2] osmium tetroxide followed by sodium bisulfate Me[5] [3] water and sulfuric acid 40. What is the maximum number of nuclei that may lie in the [4] mercuric sulfate in aqueous sulfuric acid same plane in 2-methyl-2-pentene? [5] common sense [1] 9 [2] 10 [3] 11 [4] 12 [5] 13 [1] Me[2] 47. The transition state structure thought to occur in the 41. How many sp¤Çsp‹ bonds are present in 2-methyl-2bromination of ethylene is: pentene? Br [1] 3 [2] 4 [3] 5 [4] 6 H H T2S99-11[1] 42. Which of the following is not true concerning the energy H H profile below? Which diagram below most correctly represents the [1] H [1] Cl H Cl [2] H [3] H H Cl [4] .CO 11. MPRE - PR EM MED ED4 411 T2S01-16[3] 55. Ok, lets say that bromine is attacking an alkene. Which energy profile best depicts the change in the potential energy as a function of time as a single molecule of the alkene is brominated? .CO COM D OH H 11. ED4 [4] PE [2] [3] 411 MED MPRE [3] 56. What is the name of the compound formed when cyclohexene is treated with bromine water? [1] trans-1-bromo-2-hydroxycyclohexane [2] cis-1-bromo-2-hydroxycyclohexane [3] 1-bromo-1-hydroxycyclohexane [4] trans-1,2-dibromocyclohexane [5] cis-1,2-dibromocyclohexane .CO O MPRE MED MED 411 .CO [1] OsO then NaHSO [2] dil H„SO and heat [3] BH‰, then H„O„, OH— [4] O‰ then Zn, H‰O± [5] Tequila, lime then salt .CO MPRE MED MED 411 411 .CO O MPRE MPRE [4] 53. Which is wrong as rain? MED CH3 What is the structure of compound Q? .CO Br„/H„O Br CH3 - PR E CH3 MED 411 OH OM HBr D41 [1] CH3 MPRE .CO 411 MED PRE MED 411 .CO MPRE MPRE ME MED D41 411 1.C .CO OM [4] - PR EME CH3 1.C Br [2] PRE 411 MED D Br MPRE MED MPRE CH3 .CO 411 MED MPRE Br D .CO MED 411 [4] MPRE D„/Pt 411 .CO CH3 .CO MED MPRE CH3 [3] 411 .CO 411 OH 2. NaBH [2] [1] 57. Compound Q, has the molecular formula CŒ∏HŒÁ. It reacts with one equivalent of hydrogen upon catalytic hydrogenation, and produces the following product upon reaction with bromine in carbon tetrachloride: .CO 1) Hg(OAc)„/H„O [1] [4] 411 ? MPRE M ED4 11. COM [1] Reaction coordinate .CO [5] 52. OMIT Which reagent should be utilized to effect the following transformation? MPRE - PR EM [5] None of the above MED DH [3] 411 [2] OH MPRE - PR EM COM OH HD [1] MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM M © 2001 Richard Hochstim. All rights reserved. 54. When HCl attacks isobutene (2-methylpropene) via 51. What is the major product of the reaction below? Markovnikov addition which of the following is NOT true? [1] the first step involves a proton and the π bond of the 1) BD‰, THF, 25 deg alkene, 2) H„O„, OH— [2] this is a two step reaction and the first step is rate determining. [3] the intermediate is the isobutyl cation. [4] the chloride ion attacks the intermediatein the second H OH step. [5] overall reaction is exothermic D [2] [3] [4] [5] MPRE .CO Br HCl 11. H 411 COM - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM M © 2001 Richard Hochstim. All rights reserved. 58. An optically pure compound reacts with a racemate and 64. How many of molecules below have an absolute produces an optically active mixture composed of two configuration of R? compounds. The compounds are separated by physical CH‰ CH„Cl means and subject to structural analysis. Each compound is found to contain two chiral centers, but only one of these H CH„OH CH‰ H molecules is observed to display optical active. Which of the following statements is false? O COOH CH„CBr‰ [1] The optically pure compound used initially, has three of CH„OH the same four groups on its asymmetric carbon as the does the racemate. CH‰CH„CH„ CH(CH)„ F CH‰ [2] One of the two compounds produced must be meso. [3] The two compounds produced are diastereomers. CH‰ [4] The above description can be characterized as the CH‰ resolution of enanteomers. [1] 1 [2] 2 [3] 3 [4] 4 [5] none do [5] The two products will be formed in equal amounts. [2] [5] 65. Which products will be formed in the following reaction? 59. A pair of scissors is achiral and has an internal plane of CH3 symmetry. [1] True [2] False Br MED Br [B] H Cl CH 3 [A] MED H Cl H CH3 CH3 [C] [D] MPRE .CO 411 MED MPRE .CO 411 MPRE .CO 411 MED - PR E OM 1.C D41 MPRE MPRE ME MED D41 411 1.C .CO OM [3] - PR EME MPRE .CO 411 MED MPRE .CO 411 MED Cl [4] 67. How many of the below are chiral? [A] A new boat with a steering wheel on the left. [B] A new boat with a steering wheel in the center. [C] A new pencil with no writing on it. [D] A new pencil with writing on it, [E] The cardiovascular system of a human. [1] 1 [2] 2 [3] 3 [4] 4 [5] zero PRE MED 411 .CO MPRE .CO 411 MED PRE H [1] 66. What is the relationship between A and B, and between B and C , respectively in the answer choices above? [1] enantiomers, enantiomers [2] enantiomers, diastereomers [3] diastereomers, diastereomers [4] diastereomers, enantiomers [5] diastereomers, identical [4] 63. Why are cycloalkynes which contain the triple bond in their ring only found to exist if they have a large number of ring carbons? [1] I don’t know! [2] Magic? [3] Cause small ring sizes and triple bonds cause supercritical angle strain and the whole universe could explode or implode depending on the concentration of dark matter. [3] Br [1] A,B [2] A,C [3] B,C [4] C,D [5] All will form [1] 2 [2] 3 [3] 4 [4] 6 [5] 7 [2] three chiral centers are present 62. What is the product (C) of the following reaction sequence? Propyne + NaNH„ A, A + CH‰Br B, B + NaÎ, NH‰ C [1] acetylene [2] 1-butene [3] cis-2-butene [4] trans-2-butene [5] butane H MED MPRE .CO 411 MED MPRE .CO 411 MED [B] Br MED [1] A and B [2] A and C [3] B and C [4] C only [5] none are [4] 61. How many chiral carbons are present in the sodium salt of para-hydroxybenzopenicillin? HH CH3 S CH2CONH HO CH3 N O COONa CH3 CH3 [C] .CO H CH3 CH3 411 Cl H Br .CO CH3 CH3 H 411 .CO H Br MPRE H 411 Br [A] MED CH3 H MPRE CH3 CH3 CH3 Br H MED H .CO CH3 Br 411 Br H MPRE MPRE M ED4 [2] 60. Which of the compounds below is optically active? COM MPRE M .CO MPRE [1] 76. How many chiral carbons are present in borneol, shown below? H 3C CH3 CH3 H OH 411 .CO 411 [1] 1 [2] 2 [3] 3 [4] 4 [5] 5 MPRE .CO 411 .CO MPRE MED 411 .CO [4] 71. What is the product when 3-hexyne reacts with D„/Lindlar’s catalyst? [1] cis-2,3-dideutrohexene [2] cis-3,4-dideutrohexene [3] trans-2,3-dideutrohexene [4] trans-3,4-dideutrohexene [5] 2,2,3,3-tetradeutrohexane [3] 77. Assign R/S absolute configurations to asymmetric centers a and b, respectively, in the structure below OH O O a CH3 b MED MPRE [1] 1 [2] 2 [3] 3 [4] 4 [5] 5 MPRE MED MED CH3 .CO I MPRE MED .CO C CH3 411 C Cl MED 411 Br F CH3 MPRE CH3 MED 411 411 H HO [1] R,R [2] R,S [3] S,S [4] S,R [B] CH3 [C] [D] MPRE .CO 411 MED - PR E OM D41 1.C CH3 - PR EME CH3 [4] 79. Which is a stinky electrophile? [1] BH‰ [2] O‰ [3] Na± [4] Cl„ [5] Cl± OM CH3 H 1.C OH OH H D41 [A] OH H [3] This is a tough one. 78. Which proceeds with syn addition? [1] bromination [2] halohydrin formation [3] hydrogenation of an alkyne using sodium metal and ammonia [4] hydroxylation with osmium tetroxide [5] oxymercuration demercuration [1] A only [2] B only [3] C only [4] D only [5] C and D MPRE ME [3] MED 411 .CO [4] PRE PRE MED 411 .CO MPRE MED 411 .CO MPRE MED 411 .CO MPRE MED 411 .CO MPRE MED [2] 72. Which of the following cannot be formed by the reaction of 1-methylcyclohexene with: 1. BH‰, THF, 25Î 2. H„O„, OH— or by: 1. Hg(OAc)„, H„O 2. NaBHÂ, OH— or by: 1. OsO 2. NaHSOÂ, H„O OH OH MED MED ED4 411 11. .CO [1] HgSOÂ, H„SOÂ, H„O [2] H„SO , HgSO [3] H„O [4] HgSOÂ, H„O [5] H„O„, OH— .CO CH3 MPRE - PR EM ED4 ? [4] 70. How many of these hotties have a plane of symmetry? CH3 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM M © 2001 Richard Hochstim. All rights reserved. 68. A substance identified as 2,3-dichlorobutane is found to be 73. What is the maximum number of nuclei that can lie in the optically inactive. Based upon the this information, which same plane for (CH‰)CÙCHÇCÛCÇCH„ÇCH‰? of the following are reasonable conclusions? [1] 9 [2] 10 [3] 11 [4] 12 [5] 13 A = The substance contains two chiral centers B = The substance is achiral [4] 74. Which of the following is not true of carbocations? C = The substance may be a meso compond [1] They tend to rearrange into more stable carbocations D = The substance may be a racemate [2] They often react with nucleophiles [1] A only [2] B only [3] B,C [4] B,D [5] A,B,C,D [3] They are sp¤ hybridized [4] They can lose a proton and form an alkene [5] [5] The best evidence of a carbocation intermediate is a 1,2 69. A substance identified as 1,2-dichlorobutane is found to be hydride or 1,2 alkide shift from 3Î to 2Î carbocations. optically inactive. Based upon the this information, which of the following are reasonable conclusions? [5] A = The substance contains two chiral centers 75. Which reagent should be used to preform the following B = The substance is achiral transformation? C = The substance may be a meso compond D = The substance MUST be a racemate O [1] A only [2] B only [3] B,C [4] B,D [5] A,B,C,D MPRE MPRE M MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM MPRE - PR EM MED ED4 411 11. .CO COM M © 2001 Richard Hochstim. All rights reserved. 85. Which of the following is not true of a racemate 80. Which of the structures below are meso compounds? [1] Its components are optically active Br Br [2] It is optically inactive Br Br H Br CH3 [3] It is an achiral mixture [4] It contains equal amounts levorotatory and Br CH3 dextrorotatory compounds H [5] Alterations in temperature or pressure typically cause a return to optical activity as a result of asymmetric racemic [A] [B] [C] resolution, caused by a plasma leak in the starboard warp[1] A only [2] B only [3] C only [4] A,C [5] B,C ness cell. [2] [5] 81. A mysterious hydrocarbon has a molecular formula CÈHŒ∏. 86. Which of the following will not form a meso compound? It is found to react with one equivalent of hydrogen when [1] trans-2-butene + Br„, CCl Lindlar’s catalyst is used, and with three equivalents of [2] cis-2-butene + D„, Pd/C hydrogen when palladium is used as a catalyst. How many [3] cyclohexene + OsO then NaHSO rings, double bonds and triple bonds are present in this [4] 2-butyne + D„, Lindlar’s catalyst, then H„, Pd/C mysterious compound? Oh, and please be respectively of [5] 1-butene + HBr the answer key. [1] 0,1,1 [2] 1,0,1 [3] 1,1,0 [4] 1,1,1 [5] 0,1,2 [5] 87. What orbitals are used in the C(2)ÇC(3) bond of 3-hexyne? [4] [1] spÇsp [2] sp¤Çsp [3] sp‹Çsp [4] sp¤Çsp [5] 82. How many sp orbitals used to form bonds in propyne? sp‹Çsp¤ [1] 2 [2] 3 [3] 4 [4] 5 [5] 6 MPRE .CO CH2Br 1) OsO 2) NaHSO OH CH2OH 411 MED .CO MED 411 OH CH3 MPRE OH Dinoprostone is a prostoglandin [1] 3 [2] 4 [3] 5 [4] 6 [5] 7 [2] four 89. Including dinoprostone shown below, how many stereoisomers are possible for this structure? Don’t forget to include geometric isomers, which form a subset the stereoisomer class. O MPRE .CO 411 MED MPRE .CO 411 MED MPRE 2) H„O„, OH— HO CH2Br .CO CH2 1) BH‰ OH 411 [4] H„O 411 .CO MED D41 411 1.C .CO OM MPRE - PR E OH Dinoprostone--a prostoglandin [1] 4 [2] 8 [3] 16 [4] 32 [5] 64 - PR EME [5] chiral centers + cis/trans alkenes = 6, 2fl = 64. OM MPRE 1.C .CO D41 411 MPRE ME MED PRE MED 411 .CO MPRE .CO 411 MED 411 MED HO [3] A spork too! MED COOH .CO [3] 84. Which is not chiral? [1] A cork screw [2] A pair of scissors [3] A spoon [4] A single molecule of chlorodeutroflouromethane [5] A globe with representations of the major continental land masses PRE COOH MED CH2 MED [3] Br„ CH2 MPRE [2] MPRE 411 .CO H„O„ MED 411 .CO 411 MPRE MED HBr CH2 [1] [3] 88. How many chiral centers are present in dinoprostone, shown below? O .CO [3] that is four 83. Which ain’t right? OMIT CHOICE [4] GOOD LUCK! -Rich ...
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