Organic Chemistry 1 ACS Questions Final Exam

  sp, linear - Correct Answers: Which is the correct hybridization state and geometry for the carbon atom in HCN? sp, linear sp2, trigonal planar sp3, tetrahedral None of the above This structure has one positive charge and one negative charge. - Correct Answers: The following structure has been drawn without formal charges. Which statement describes the missing formal charge(s)? This structure has one positive charge and one negative charge. This structure has one positive charge but no negative charges. This structure has one negative charge but no positive charges. This structure has no formal charges. sp2-sp3 - Correct Answers: The indicated σ bond results from the overlap of which orbitals? sp2-sp2 sp-sp3 sp-sp2 sp2-sp3 Trigonal planar - Correct Answers: Of the following molecular geometries, which has the largest bond angle? Pyramidal Tetrahedral Trigonal planar Bent 13 - Correct Answers: How many σ bonds are in the following compound? 8 9 13 14 Y, because the dipole moments do not fully cancel. - Correct Answers: Which compound has the higher boiling point? Explain briefly. X, because the dipole moments are far apart. Y, because the dipole moments do not fully cancel. Y, because it is less branched. X, because it is more linear. 6 - Correct Answers: How many hydrogen atoms are in the compound represented by the following bond-line drawing? 5 6 7 8 D) 9 5 - Correct Answers: The compound represented by the following bond-line drawing has how many carbon atoms and how many π bonds? C atoms π bonds (a) 10 6 (b) 10 5 (c) 9 6 (d) 9 5 C - Correct Answers: All of the following are significant resonance structures of the benzyl carbocation, EXCEPT: A - Correct Answers: Which of the following resonance structures is the most significant contributor to the resonance hybrid? D - Correct Answers: Which of the following structures exhibits an sp3-hybridized nitrogen atom? C - Correct Answers: Which is a bond-line drawing of (CH3)2CHCH2OC(CH3)3? C - Correct Answers: Which of the following has the correct curved arrow(s) placement to show resonance for the given allylic carbocation? A - Correct Answers: Which of the following anions is resonance delocalized? A - Correct Answers: The following cation has a total of how many resonance structures? D - Correct Answers: Which of the following best represents the resonance hybrid of the given anion? B - Correct Answers: Which of the following does NOT represent a pair of resonance structures? C - Correct Answers: What is the strongest base that is present after methyl magnesium bromide (CH3MgBr) is treated with water? The right side - Correct Answers: Which side of the following equilibrium is favored? The right side. The left side. Depends on temperature. Cannot determine without more information. C - Correct Answers: All of the following are more acidic than water (H2O) EXCEPT: D - Correct Answers: All of the following are Lewis bases EXCEPT: II III I - Correct Answers: Arrange the following compounds in order of increasing acidity, from the weakest acid to the strongest acid. II I III II III I I III II III II I HBr is the stronger acid because Br is larger than Cl. - Correct Answers: Which is the stronger acid, HCl or HBr? Explain briefly. HCl is the stronger acid because Cl is more electronegative than Br. HCl is the stronger acid because Cl is smaller than Br. HBr is the stronger acid because Br is less electronegative than Cl. HBr is the stronger acid because Br is larger than Cl. Proton D - Correct Answers: Which of the indicated protons in the given compound is the most acidic? Proton A Proton B Proton C Proton D Y is the stronger acid because its conjugate base is stabilized by resonance. - Correct Answers: Which of the given compounds is more acidic? Briefly explain. X is the stronger acid because the acidic proton is on a more electronegative atom. X is the stronger acid because its conjugate base is stabilized by inductive effects. Y is the stronger acid because its conjugate base is stabilized by resonance. Y is the stronger acid because the acidic proton is stabilized by inductive effects. A - Correct Answers: Of the following, which is the strongest base? D - Correct Answers: All of the following are representations of cis-1,2-dimethylcyclohexane, EXCEPT: B - Correct Answers: All of the following are representations of 2-methylpentane, EXCEPT: C - Correct Answers: Which of the following is expected to have the largest heat of combustion? D - Correct Answers: Which of the following is a constitutional isomer of heptane? 2,3-dimethylhexane - Correct Answers: Provide a systematic name for the following compound. 4-isopropylpentane 2-isopropylpentane 5,6-dimethylhexane 2,3-dimethylhexane C - Correct Answers: Which of the following represents the most stable conformation of cis-1,4-dimethylcyclohexane? B - Correct Answers: Which of the following conformers has one or more gauche interactions? C - Correct Answers: Which of the following represents the most stable conformation of the given compound? (1,1-dimethylethyl) - Correct Answers: Which of the following is the correct IUPAC name for the tertbutyl substituent? (1,1-dimethylethyl) (1,1,1-trimethyl) (1-methyl-2-propyl) 2-methyl-2-propyl) R - Correct Answers: What is the configuration of the chiral center in the following compound? R S Z Depends on T Diastereomers - Correct Answers: What is the relationship between the following two compounds? Enantiomers Diastereomers Constitutional isomers Resonance forms D - Correct Answers: Which of these compounds is expected to be optically active at room temperature? II only - Correct Answers: Identify the meso compound(s). I only II only I and III only I, II, and III It is not chiral, and it does not have an enantiomer. - Correct Answers: Is the following compound chiral, and does it have an enantiomer? It is not chiral, and it does not have an enantiomer. It is not chiral, but it does have an enantiomer. It is chiral, and it has an enantiomer. It is chiral, but it does not have an enantiomer. II I III - Correct Answers: Arrange the given substituents in order of increasing priority (based on Cahn-Ingold-Prelog rules), from lowest to highest priority. III II I III I II II I III I II III Keq 1 - Correct Answers: For a reaction with ΔG 0, which of the following MUST be true? The reaction must be exothermic The reaction must be endothermic Keq 1 None of the above D - Correct Answers: Which of the following can serve as a nucleophile? II and IV - Correct Answers: In the following energy diagram showing the progress of a reaction, which location(s) represent an intermediate? I, III, and V II and IV Only III I, II, III, IV, and V ΔS 0 - Correct Answers: Which best describes the change in entropy for the following reaction? ΔS 0 ΔS = 0 ΔS 0 ΔS = 1 A - Correct Answers: Which best represents the transition state of the following reaction? The bonds broken are weaker than the bonds formed. - Correct Answers: For a reaction with ΔH 0, which of the following must be true? All bonds are broken homolytically. All bonds are broken heterolytically. The bonds broken are stronger than the bonds formed. The bonds broken are weaker than the bonds formed. bimolecular - Correct Answers: The rate expression for a reaction was found to be: Rate=k[Et Br][Na Sh] This reaction is best described as zero order bimolecular unimolecular rate-determining proton transfer, followed by loss of a leaving group - Correct Answers: What type of reaction steps are represented below? loss of a leaving group, followed by loss of a leaving group proton transfer, followed by loss of a leaving group nucleophilic attack, followed by proton transfer proton transfer, followed by nucleophilic attack The reaction proceeds via a carbocation intermediate. - Correct Answers: For the following substitution reaction, which statement is FALSE? The process is bimolecular. Increasing the concentration of hydroxide will cause an increase in the rate of reaction. The use of a polar aprotic solvent will enhance the rate. The reaction proceeds via a carbocation intermediate. D - Correct Answers: Which is the major product of this reaction? C - Correct Answers: Of the following, which is the most efficient synthesis of 1-butene (CH3CH2CH═CH2)? Increased steric hindrance - Correct Answers: Which of the following is NOT favorable for an SN2 reaction? A leaving group on a primary carbon atom A polar aprotic solvent A strong nucleophile Increased steric hindrance SN1 - Correct Answers: Which mechanism involves a carbocation electrophile reacting with a weak nucleophile? SN1 SN2 E1 E2 B - Correct Answers: Which of the following best represents the transition state of the rate-determining step for the given reaction? c. II and IV - Correct Answers: Sodium ethoxide (NaOEt) is a suitable reagent to promote which mechanism(s)? SN1 SN2 E1 E2 a.I and II b.I and III c. II and IV d. III and IV t-BuOK - Correct Answers: Which is the best reagent to achieve the following transformation? t-BuOK NaOH CH3OH Conc. H2SO4 D - Correct Answers: Which substrate undergoes the fastest solvolysis reaction with methanol (CH3OH)? I is faster because it has less steric hindrance. - Correct Answers: Which is the faster reaction and why? I is faster because it has a better nucleophile. I is faster because it has less steric hindrance. II is faster because it has the better leaving group. II is faster because it has the more stable carbocation. C - Correct Answers: Which disconnection leads to the most reasonable retrosynthesis of the given target molecule? A - Correct Answers: Which of the following is not a reasonable retrosynthesis? C - Correct Answers: Which of the following compounds is NOT a product of this ozonolysis reaction? D - Correct Answers: Which of the following represents an efficient method for preparing the alcohol shown? I and II - Correct Answers: Consider the following acid-catalyzed hydration reaction: Which of the following ions are intermediates in the accepted mechanism for this process? I, II, and III I and II None of the above. The process is concerted. Only IV D - Correct Answers: Provide suitable reagents for the following transformation. B - Correct Answers: Predict the major product of the following reaction. C - Correct Answers: Which of the following represents a likely step in the mechanism of the given reaction? D - Correct Answers: Of the following, which is the most stable alkene? (E)-3-(1-methylethyl)-2-heptene - Correct Answers: What is the IUPAC name of the given compound? (E)-3-butyl-4-methyl-2-pentene (Z)-3-butyl-4-methyl-2-pentene (E)-3-(1-methylethyl)-2-heptene (Z)-3-(2-propyl)-2-heptene A - Correct Answers: Which of the following compounds is converted into carbon dioxide and acetic acid (CH3CO2H) upon ozonolysis? C - Correct Answers: All of the following methods can be used to prepare 2-butanone (CH3COCH2CH3) EXCEPT: Na, NH3 - Correct Answers: Which reagents will achieve the following transformation? H2, Pt NaNH2/NH3 Na, NH3 H2, Lindlar's catalyst xs HBr - Correct Answers: Which reagent (or reagents) will achieve the following transformation? Br2 Br2, H2O xs HBr, ROOR xs HBr B - Correct Answers: Which reagents will achieve the following transformation? A. 1) H2, Lindlar's cat.; 2) RCO3H; 3) H3O+ B. 1) H2, Lindlar's cat.; 2) KMnO4 C. 1) Na, NH3; 2) KMnO4 D. 1) KMnO4; 2) H2, Pd B - Correct Answers: Which is the best retrosynthesis of the given target molecule? C - Correct Answers: Which disconnection leads to the most reasonable retro-synthesis of the given target molecule? D - Correct Answers: Predict the major product of the following reaction sequence: C - Correct Answers: What is the major product of the following reaction? Only I, II, and III - Correct Answers: Determine which of the following reactions is expected to be thermodynamically favorable: I, II, III, and IV Only I, II, and III Only III Only II and III C - Correct Answers: Which of the following is an intermediate when 1-butene undergoes radical bromination? D - Correct Answers: Of the following, which is the most stable radical? B - Correct Answers: Which of the following cycloalkanes gives a total of four monochlorination products (disregarding stereoisomers)? A - Correct Answers: Which of the following is a likely intermediate when 1-pentene undergoes addition of HBr, in the presence of peroxides? D - Correct Answers: Identify the most likely initiation step in the bromination of 2-methylpropane. NaC≡CH, followed by H2 and Lindlar's catalyst - Correct Answers: What are the best reagents to accomplish this transformation? t-BuOK NaC≡CH, followed by H2 and Pt NaC≡CH, followed by H2 and Lindlar's catalyst NaOH, followed by t-BuOK C - Correct Answers: Which of the following represents an efficient synthesis of 1-methylcyclohexene? D - Correct Answers: Which reaction sequence best accomplishes this transformation? Addition, followed by elimination - Correct Answers: Which of the following describes an efficient strategy for moving the location of a π bond? Substitution, followed by addition Addition, followed by substitution Elimination, followed by addition Addition, followed by elimination Ozonolysis - Correct Answers: Which of the following reactions can be utilized to shorten the length of a carbon chain? Reduction Elimination Ozonolysis Epoxidation B - Correct Answers: Which reaction sequence best accomplishes the given transformation? A - Correct Answers: Which of the following represents a logical retrosynthesis of the given diol target molecule? PCC, CH2Cl2 - Correct Answers: Of the following, which are the best reagents to perform the given transformation? Na2Cr2O7, H2SO4, H2O CrO3, H3O+, acetone PCC, CH2Cl2 KMnO4, NaOH, cold D - Correct Answers: Which of the following is NOT an efficient synthesis of 2-methyl-2-pentanol? B - Correct Answers: What is the major product of the given reaction? D - Correct Answers: A logical retrosynthesis of the given target molecule leads to which Grignard reagent? C - Correct Answers: Predict the major product of the following sequence of reactions. B - Correct Answers: What is the missing reagent in the following synthesis? A - Correct Answers: Predict the major product of the following sequence of reactions. A - Correct Answers: Which reagent (or reagents) will efficiently achieve the following transformation? B - Correct Answers: Which of the following methods would successfully prepare the given target molecule? D - Correct Answers: Which of the following is a likely intermediate in the mechanism for the given reaction? A - Correct Answers: Which of the following is one of the products formed in the given reaction? A - Correct Answers: In the retrosynthetic analysis of the given target molecule, which disconnection leads to an epoxide starting material? C - Correct Answers: Predict the major product of the following reaction. B - Correct Answers: Which reagents will achieve the following transformation? D - Correct Answers: Which is the best retrosynthesis of the given target molecule? C - Correct Answers: Predict the major product of the following reaction.