OChem
C
How many chiral carbons are there in the following molecule (the naturally occurring stereoisomer is the male hormone testosterone)? A. three B. four C. six D. seven
C
How many hydrogen atoms are there in nonane, the linear hydrocarbon with nine carbon atoms? A. 16 B. 18 C. 20 D. 22
C
What is (are) the major organic product(s) obtained from the following reaction? 1. (R)-2-bromo-3-methylbutane 2. (S)-2-bromo-3-methylbutane 3. 2-bromo-2-methylbutane A. Only 1 B. Only 2 C. Only 3 D. Only 1 and 2
A
What is (are) the major organic product(s) obtained from the following reaction? A. only 1 B. only 2 C. only 3 D. only 2 and 3
D
What is the IUPAC name of the following compound? A. (E)-1-chloro-1,2,3-trimethyl-1-butene B. (Z)-1-chloro-1,2,3-trimethyl-1-butene C. (E)-2-chloro-3,4-dimethyl-2-pentene D. (Z)-2-chloro-3,4-dimethyl-2-pentene
B
What is the IUPAC name of the following compound? A. (R)-4-methyl-2-hexyne B. (S)-4-methyl-2-hexyne C. (R)-3-methyl-4-hexyne D. (S)-3-methyl-4-hexyne
B
What is the IUPAC name of the following compound? A. (Z)-3-ethyl-5-methyl-1,4-heptadiene B. (E)-3-ethyl-5-methyl-1,4-heptadiene C. (E)-3-methyl-5-vinyl-3-heptene D. (Z)-1,3-diethyl-1-methyl-1,4-pentadiene
B
What is the IUPAC name of the following compound? A. 1,3-dimethylhexene B. 2,4-dimethyl-2-hexene C. 2,4-dimethyl-1-hexene D. 3,5-dimethyl-4-hexene
B
What is the IUPAC name of the following compound? A. 1-isopropyl-4,6-dimethylcyclohexane B. 1-isopropyl-2,4-dimethylcyclohexane C. 4-isopropyl-1,3-dimethylcyclohexane D. 4-isopropyl-1,5-dimethylcyclohexane
A
What is the IUPAC name of the following compound? A. 3,4-dimethyl-1-hexen-5-yne B. 4-ethynyl-2-vinylbutane C. 3-methyl-4-vinyl-1-pentyne D. 4-ethynyl-3-methyl-1-pentyne
D
What is the IUPAC name of the following compound? A. 5,5-dimethyl-3-ethylheptane B. 5-ethyl-3,3-dimethyl-heptane C. 3,3-dimethyl-5-ethylheptane D. 3-ethyl-5,5-dimethyl-heptane
B
What is the IUPAC name of the following compound? A. trans-1-isopropyl-4-methylcyclohexane B. cis-1-isopropyl-4-methylcyclohexane C. cis-2-isopropyl-5-methylcyclohexane D. cis-1-tert-butyl-4-methylcyclohexane
B
What is the IUPAC name of the following compound? CH₃CH₂CH₂-C≡C-CH(CH₃)₂ A. 1-isopropyl-1-pentyne B. 2-methyl-3-heptyne C. 6-methyl-4-heptyne D. isopropyl propyl ethyne
D
What is the approximate C-C-C bond angle in propane? A. 90 B. 109 C. 120 D. 180
C
What is the approximate C-C-C bond angle in propene, CH₃CH=CH₂? A. 90° B. 109° C. 120° D. 180°
C
What is the approximate value of the C-C-C bond angle in propene? A. 90 B. 109 C. 120 D. 180
D
What is the characteristic of a radical chain termination step? A. Radicals are formed B. Substitution products are formed C. A radical reacts with a molecule to give a new radical and a new molecule D. Two radicals combine to give a molecule
D
What is the configuration of the two chiral centers in the following molecule? A. 3R, 5R B. 3R, 5S C. 3S, 5R D. 3S, 5S
B
What is the correct assignment of the acid, base, conjugate acid and conjugate base in the following equilibrium? A. 1 = acid; 2 = base; 3 = conjugate acid; 4 = conjugate base B. 1 = acid; 2 = base; 3 = conjugate base; 4 = conjugate acid C. 1 = base; 2 = acid; 3 = conjugate acid; 4 = conjugate base D. 1 = base; 2 = acid; 3 = conjugate base; 4 = conjugate acid
C
What is the correct assignment of the names of the following compounds? 1. CH₃Cl 2. CH₂CL₂ 3. CHCl₃ A. 1 = methyl chloride; 2 = chloroform; 3 = methylene chloride B. 1 = trichlor; 2 = chloroform; 3 = methylene chloride C. 1 = methyl chloride; 2 = methylene chloride; 3 = chloroform D. 1 = chloroform; 2 = methylene chloride; 3 = trichlor
A
What is the correct order of exothermicity for hydrogenation of the following butanes upon treatment with H2/Pd (more exothermic > less exothermic)? A. 1 > 2 > 3 B. 1 > 3 > 2 C. 3 > 2 > 1 D. 2 > 3 > 1
D
What is the correct order of stability of the following carbocations (more stable > less stable)? A. 1 > 2 > 3 B. 1 > 3 > 2 C. 3 > 1 > 2 D. 3 > 2 > 1
C
What is the correct order of stability of the following radicals (more stable > less stable)? A. 1 > 2 > 3 B. 2 > 1 > 3 C. 2 > 3 > 1 D. 3 > 2 > 1
D
What is the correct order of the Cahn-Ingold-Prelog ranking of the following substituents as used in assigning R and S configurations of chiral centers? (higher ranking > lower ranking) 1.-CH₂OH 2.-CHO 3.-OCH₃ 4.-OCOCH₃ A. 3 > 4 > 1 > 2 B. 4 > 3 > 1 > 2 C. 3 > 4 > 2 > 1 D. 4 > 3 > 2 > 1
B
What is the equation for the rate of formation of 1-iodobutane from the reaction of 1-chlorobutane (BuCl) with NaI by an Sn2 mechanism? A. Rate = k[BuCl] B. Rate = k[BuCl][NaI] C. Rate = k[NaI] D. Rate = k[BuCl]2
B
What is the geometry of the central carbon atom of tert-butyl radical? A. tetrahedral B. Trigonal Planar C. Trigonal Pyramidal D. Square Planar
B
What is the ground-state electronic configuration of a nitrogen atom (nitrogen: atomic number 7)? A. 1s²2s¹2p⁴ B. 1s²2s²2p³ C. 1s¹2s¹2p⁵ D. 1s²2s²2p²
D
What is the hybridization of carbon atoms labeled i - iii in the following structure? A. i = sp²; ii = sp²; iii = sp² B. i = sp; ii = sp; iii = sp³ C. i = sp²; ii = sp; iii = sp³ D. i = sp²; ii = sp²; iii = sp³
D
What is the index of hydrogen deficiency of a compound with a molecular formula of C₆H₈? A. 0 B. 1 C. 2 D. 3
B
What is the index of hydrogen deficiency of a compound with a molecular formulate of C₅H₉Br? A. 0 B. 1 C. 2 D. 3
C
What is the major organic product obtained from the following raction? A. 1 B. 2 C. 3 D. 4
A
What is the major organic product obtained from the following reaction? A. (E) 3,4-dibromohexene B. (Z) 3,4-dibromohexene C. (E) 2,3-dibromohexene D. (Z) 2,3-dibromobutene
A
What is the major organic product obtained from the following reaction? A. 1 B. 2 C. 3 D. 4
B
What is the major organic product obtained from the following reaction? A. 1 B. 2 C. 3 D. 4
C
What is the major organic product obtained from the following reaction? A. 1 B. 2 C. 3 D. 4
D
What is the major organic product obtained from the following reaction? A. 1 B. 2 C. 3 D. 4
B
What is the major organic product obtained from the following reaction? A. 2-methyl-3-hexene B. 2-methyl-3-heptyne C. 2-bromo-3-methylbutane D. 2-methyl-2-butene
D
What is the major organic product obtained from the following reaction? A. Butane B. 1-butene C. cis-2-butene D. trans-2-butene
C
What is the major organic product obtained from the following reaction? A. butane B. 1-butene C. cis-2-butene D. trans-2-butene
C
What is the major product formed upon radical bromination of (S)-3-methylhaxane? A. (S) 3-bromo-3-methylhaxane B. (R) 3-bromo-3-methylhaxane C. a mixture of (R) and (S) 3-bromo-3-methylhexane D. (3R) 1-bromo-3-methylhexane
B
What is the name of the following compound? A. vinylcyclohexane B. allylcyclohexane C. methylenecyclohexane D. Propargylcyclohexane
D
What is the relationship between the following pair of structures? A. They are enantiomers B. They are diastereomers C. They are constitutional isomers D. They are identical
C
What is the smallest trans cycloalkene that is stable at room temperature? A. (E)-cyclohexene B. (E)-cycloheptene C. (E)-cyclooctene D. (E)-cyclodecene
B
What type of reaction mechanism accounts for the reaction of an alkene with aqueous acid to give an alcohol? A. Nucleophilic addition B. Electrophilic addition C. Radical addition D. Elimination
C
What type of reactive intermediate is formed in the reaction of propene with N-bromosuccinimide to give 3-bromo-1-propene? A. Allylic carbocation B. Allylic carboanion C. Allylic Radical D. Cyclic bromonium ion
C
Which atomic orbitals overlap to form the carbon-carbon triple bond of an alkyne? A. 2s+2s; sp+sp, 2p+2p B. sp+sp; sp+sp; 2p+2p C. sp+sp; 2p+2p; 2p+2p D. sp2+sp2; sp+sp; 2p+2p
C
Which atomic orbitals overlap to form the carbon-hydrogen σ bonding molecular orbitals of ethane, CH₃CH₃? A. C2p+H1s B. C2sp+H1s C. C2sp²+H1s D. C2sp³+H1s
A
Which o the following is NOT a characteristic of SN1 reactions? A. The electrophilic carbon undergoes inversion of stereochemistry B. The rate is proportional to the concentration of substrate C. The reaction proceeds faster in a more polar solvent D. The rate is independent of the concentration of nucleophile
C
Which of the following Newman projections dos NOT represent 2-methylhexane? A. 1 B. 2 C. 3 D. 4
D
Which of the following Newman projections represents the most stable conformation of 2-methylbutane? A. 1 B. 2 C. 3 D. 4
B
Which of the following accounts for the anti-Markkovnikow regiochemistry of the reaction of an alkene with HBr in the presence of peroxides? A. The alkene reacts with HBr to give a carbocation B. The alkene reacts with a bromine atom to give a radical C. The alkene reacts with a hydrogen aim to give a radical D. The alkene reacts with peroxide to give an allylic radical
D
Which of the following alkanes has the highest boiling point? A. Propane B. Butane C. Pentane D. Hexane
B
Which of the following alkenes is most likely to undergo rearrangement upon acid-catalyzed hydration (treatment with aqueous H2SO4)? A. 1 B. 2 C. 3 D. 4
D
Which of the following alkenes undergoes the most exothermic hydrogenation upon treatment with H2/Pd? A. 1 B. 2 C. 3 D. 4
D
Which of the following alkyl halides undergoes the fastest SN2 reaction with sodium azide, naN 3? A. 1-fluorohexane B. 1-chlorohexane C. 1-bromohexane D. 1-iodohexane
D
Which of the following alkyl halides undergoes the fastest solvolysis reaction with ethanol, CH3CH2OH? A. methyl fluoride B. ethyl bromide C. 2-chloropropane D. Tert-butyl bromide
D
Which of the following anions is the best leaving group in an SN1 reaction? A. F- B. HO- C. NH2- D. Cl-
D
Which of the following bonds has the lowest bond dissociation enthalpy? A. C-H B. C-F C. C-Br D. C-I
B
Which of the following bonds has the smallest dipole moment? A. Li-Cl B. C-H C. O-H D. H-Cl
D
Which of the following compounds does NOT have a hydrogen deficiency of 5? A. 1 B. 2 C. 3 D. 4
B
Which of the following compounds is an aldehyde? A. CH₃CH₂CH₂COOH B. CH₃CH₂CHO C. CH₃CH₂CH₂OH D. CH₃CH₂COCH₃
C
Which of the following compounds is most susceptible to auto oxidation? A. propene B. 1,3-butadiene C. 1,4-pentadiene D. 1,5-hexadiene
A
Which of the following compounds is/are chiral? A. only 1 B. only 1 and 2 C. only 2 and 3 D. 1, 2 and 3
B
Which of the following concepts can be used to rationalize the observation that acetic acid is a stronger acid than methanol? A. Electronegativity B. Resonance C. Valence shell electron pair repulsion theory D. Pauli exclusion principle
A
Which of the following cycloalkanes has the smallest heat of combustion per carbon atom? A. cyclopropane B. cyclopentane C. cyclohexane D. cycloheptane
C
Which of the following elements has the highest electronegativity? A. N B. C C. O D. S
A
Which of the following energy diagrams represents the course of an exothermic Sn1 reaction? A. 1 B. 2 C. 3 D. 4
B
Which of the following has the list of compounds in the correct order of decreasing boiling point (higher boiling point > lower boiling point)? A. Chloromethane > chloroethane > 2-chloropropane > 2-chloro-2-methylpropane B. 2-chloro-2-methylpropane > 2-chlrorpropane > chloroethane >chloromethane C. Chloroethane > chloromethane > 2-chloro-2-methylpropane > 2-chloropropane D. Chloromethane > 2-chloro-2-methylpropane > 2-chloropropane > chloroethane
C
Which of the following has the list of compounds in the correct order of decreasing density (higher density > lower density)? A. CH₂CL₂ > CH₂Br₂ > CH₂I₂ B. CH₂Cl₂ > CH₂I₂ > CH₂Br₂ C. CH₂I₂ > CH₂Br₂ > CH₂Cl₂ D. CH₂I₂ > CH₂Cl₂ > CH₂Br₂
C
Which of the following has the lowest pKa? A. butane B. 1-butene C. 1-butyne D. 2-butyne
C
Which of the following is NOT true regarding the properties of alkanes? A. Alkanes are non polar B. Alkanes burn in air to give H₂O and CO₂ C. Alkanes are highly miscible with water D. The strongest intermolecular force between alkane molecules is the van der Waals interaction
D
Which of the following is Not a characteristic of SN2 reactions? A. The electrophilic carbon undergoes inversion of stereochemistry B. The rate is proportional to the concentration of substrate C. The rate is proportional to the concentration of nucleophile D. The rate is independent of the solvent
A
Which of the following is a definition of the activation energy of a reaction? A. The difference in Gibbs free energy between the reactants and the transition state B. The difference in Gibbs free energy between the reactants and the intermediate C. The difference in Gibbs free energy between the reactants and the product D. The difference in Gibbs free energy between the transition state and the product
A
Which of the following is a feature of a Bronsted-Lowry acid? A. Proton donor B. Proton acceptor C. Electron pair donor D. Electron pair acceptor
D
Which of the following is a feature of a Lewis acid? A. Proton donor B. Proton acceptor C. Electron pair donor D. Electron pair acceptor
C
Which of the following is a primary amine? A. 1 B. 2 C. 3 D. 4
C
Which of the following is a tertiary alcohol? A. 1 B. 2 C. 3 D. 4
A
Which of the following is an accurate statement of Hammond's postulate? A. The transition state of an exothermic reaction will resemble the starting materials (reactants) more than the product B. The transition state of an exothermic reaction will resemble the products more than the starting materials (reactants) C. The transition state of an endothermic reaction will resemble the starting materials (reactants) more than the product D. The difference in energy between the starting materials (reactants) and transition state controls the rate of reaction.
A
Which of the following is an ester? A. 1 B. 2 C. 3 D. 4
D
Which of the following is easiest to deprotonate? A. CH₄ B. CH₃CH₃ C. CH₂=CH₂ D. HC≡CH
B
Which of the following is most likely to undergo rearrangement during reaction with methanol? A. 1 B. 2 C. 3 D. 4
D
Which of the following is the best definition of a pair of atropisomers? A. A pair of enantiomers which do not interconvert B. A pair of enantiomers which lack chiral centers C. A pair of enantiomeric structures which lack chiral centers and interconvert by rotation around carbon-carbon single bonds D. A pair of enantiomers which lack chiral centers and do not interconvert because of hindered rotation around carbon-carbon single bonds
C
Which of the following is the definition of a pair of diastereomers? A. A pair of structures that are superposable mirror images of one another B. A pair of stereoisomers that are non-superposable mirror images of one another C. A pair of stereoisomers that are not mirror images of one another D. A pair of stereoisomers that have equal specific rotations
B
Which of the following is the definition of a pair of enantiomers? A. A pair of structures that are superposable mirror images of one another B. A pair of stereoisomers that are non-superposable mirror images of one another C. A pair of stereoisomers that are not mirror images of one another D. A pair of stereoisomers that have equal specific rotations
A
Which of the following is the most nucleophilic? A. Sodium ethoxide B. Acetic acid C. Methanol D. Water
B
Which of the following is the strongest acid? A. HCl B. HI C. HF D. HBr
B
Which of the following molecules has a molecular dipole? A. 1 B. 2 C. 3 D. 4
D
Which of the following reactions corresponds to a substitution? A. propene --> 1,2-dibromopropane B. 1-iodopropane --> propene C. Propene --> propane D. 1-iodopropane --> 1-bromopropane
B
Which of the following reactions of alkenes takes place with syn stereospecificity? A. Addition of bromine (Treatment with Br2) B. Hydrogenation (treatment with H2/Pt) C. Addition of HBr (treatment with HBr) D. Acid-catalyzed hydration (treatment with aqueous H2SO4)
A
Which of the following represents the transition state of the rate-determining step in the reaction between tert-butyl bromide and methanol? A. 1 B. 2 C. 3 D. 4
B
Which of the following resonance structures makes the largest contribution to the structure of [H2CCHO]-? A. 1 B. 2 C. 3 D. 4
D
Which of the following sets consists of only polar aprotic solvents? A. water, hexane, methanol B. acetic acid, DMF, toluene C. DMSO, ethanol, acetonitrile D. DMF, acetonitrile, DMSO
C
Which of the following shows curved arrows that correctly accounts for the differences between the two structures? A. 1 B. 2 C. 3 D. 4
B
Which of the following solvents is the best choice for the reaction of 1-chlorohexane with sodium bromide? A. water B. N,N-dimethylformamide C. hexane D. toluene, PhCH3
D
Which of the following statements is NOT true regarding pairs of enantiomers? A. They have identical melting points B. They have identical boiling points C. They rotate plane polarized light in opposite directions D. They react at identical rates with chiral reagents
B
Which of the following statements is NOT true regarding sN1 reactions? A. A carbocation intermediate is formed B. The mechanism has only one step C. Polar, protic solvents are good choices for SN1 reactions D. The stereochemical outcome is racemization at the carbon bearing the leaving group
B
Which of the following statements is Not true about the allyl radical? A. The carbon-carbon bond lengths are identical B. The unpaired electron density is shared between carbons 1 and 2 C. It undergoes reaction with bromine to give a single product D. IT is formed by abstraction of hydrogen atom from the methyl group of propene
B
Which of the following statements relates to SN1 reactions is not true? A. The heterolysis of a bond between atoms which do not bear formal charges always produces a cation and an anion B. The charged carbon atom of a carbocation has a complete octet of valence shell electrons C. Carbocations are Lewis acids D. Nucleophiles seek centers of low electron density
B
Which of the following structures is different from the other three? A. 1 B. 2 C. 3 D. 4
B
Which of the following substituents has the highest priority according to the Cahn-Ingold-Prelog system used in assigning R and S Configurations? A. -NH₂ B. -NHCH₃ C. -CH₂NH₂ D. -CH₂NHCH₃
B
Which set of curved arrows accounts for the deprotonation of an acid (A-H) by a base (:B)? A. 1 B. 2 C. 3 D. 4
D
Which sets of curved arrows accounts for the protonation of propene with HI? A. 1 B. 2 C. 3 D. 4
D
Which species is the conjugate acid in the following acid-base reaction? A. 1 B. 2 C. 3 D. 4
C
Wich of the following is the strongest acid? A. CH₃CH₃ B. CH₃NH₂ C. CH₃OH D. CH₃F