ACS - Alkanes, Alkenes, Alkynes and their Alicyclic Couterparts

Addition of 1 equivalent of bromine to 2,4-hexadiene at 0º C gives 4,5-dibromo-2-hexene plus an isomer.Which of the following is that isomer? A) 5,5-dibromo-2-hexene B) 2,5-dibromo-3-hexene C) 2,2-dibromo-3-hexene D) 2,3-dibromo-4-hexene

B) 2,5-dibromo-3-hexene

Which of the following C6H12 isomers has the largest heat of combustion? A) cyclohexane B) methylcyclopentane C) ethylcyclobutane D) propylcyclopropane

D) propylcyclopropane

What reagent(s) would best achieve conversion of 3,3-dimethyl-1-butyne to the aldehyde (CH3)3CCH2CHO? A) H3O(+) and catalytic Hg(+2) B) (i) R2BH in ether ( R=C5H11 ) (ii) H2O2 and aqueous NaOH C) KMnO4 in aqueous NaOH D) (i) HOBr (ii) aqueous NaOH

B) (i) R2BH in ether ( R=C5H11 ) (ii) H2O2 and aqueous NaOH

Which of the following reagents and conditions would best serve to convert 1-butyne to 1,1-dibromobutane? A) 2 equivalents of HBr, no peroxides. B) 2 equivalents of HBr, with peroxides. C) 1 equivalent of Br2. D) 2 equivalents of Br2 followed by i equivalent of KOH.

B) 2 equivalents of HBr, with peroxides.

Which one of the following compounds contains the greatest number of sp hybridized carbon atoms? A) 1,4-Cyclooctadiene B) 2,5-dimethyl-2,3,4-hexatriene C) Phenylacetylene D) 1,1-diallyl-3,3-divinylcyclobutane

B) 2,5-dimethyl-2,3,4-hexatriene

How many sp hybridized carbon atoms are present in a molecule of 3-methyl-4-vinyl-1,2-heptadien-5-yne? A) 2 B) 3 C) 4 D) 5

B) 3

Reaction of 3,3,6,6-tetramethyl-1,4-cyclohexadiene, first with excess aqueous mercuric acetate, then followed by sodium borohydride reduction, produces a mixture of isomeric C10H20O2 alcohols.Excluding enantiomers, how many isomeric products may be formed in this reaction? A) 2 B) 4 C) 6 D) 8

B) 4

The radical halogenation of 2-methylpropane gives two products: (CH3)2CHCH2X (minor) and (CH3)3CX (major) Chlorination gives a larger amount of the minor product than does bromination, Why? A) Bromine is more reactive than chlorine and is able to attack the less reactive 3º C-H. B) Bromine atoms are less reactive (more selective) than chlorine, and preferentially attack the weaker 3º C-H bond. C) The methyl groups are more hindered to attack by the larger bromine atom. D) Bromination is reversible and the more stable 3º-alkyl bromide is formed exclusively.

B) Bromine atoms are less reactive (more selective) than chlorine, and preferentially attack the weaker 3º C-H bond.

Which compound is a likely product from addition of Cl2 to 1-butene? A) CH3CH2CH2CHCl2 B) CH3CH2CHClCH2Cl C) ClCH2CH2CH2CH2Cl D) CH3CH2CCl2CH3

B) CH3CH2CHClCH2Cl

Which reaction conditions would best convert 3-hexyne to cis-3-hexene? A) Pt catalyst and H2. B) Lindlar's Pd catalyst and H2. C) Na in liquid NH3. D) NaNH2 in liquid NH3.

B) Lindlar's Pd catalyst and H2.

Which of the following isomers has the lowest heat of combustion? A) cis-1,2-dimethylcyclohexane B) trans-1,2-dimethylcyclohexane C) cis-1,3-dimethylcyclohexane D) trans-1,3-dimethylcyclohexane

C) cis-1,3-dimethylcyclohexane

The most typical reaction of simple alkenes is ... A) electrophilic substitution B) nucleophilic substitution C) electrophilic addition D) nucleophilic addition

C) electrophilic addition

Which of the following reactions of cyclohexene may be considered an oxidation? A) addition of hydrogen (Pt catalyst) to give cyclohexane. B) addition of HBr to give bromocyclohexane C) epoxidation by perbenzoic acid to give cyclohexene oxide D) mercuric acetate catalyzed hydration to give cyclohexanol

C) epoxidation by perbenzoic acid to give cyclohexene oxide

The product from OsO4 hydroxylation of trans-2-butene will be ... A) achiral B) optically active C) racemic D) a meso compound

C) racemic

How many isomeric pentenes (C5H10) exist? (count stereoisomers as well) A) 4 B) 5 C) 6 D) 7

C) 6

Peroxide induced reaction of carbon tetrachloride with 1-butene produces which of the following? A) 1,1,1,3-tetrachloropentane. B) 1,1,1,2-tetrachloropentane. C) 1-chloro-2-trichloromethylbutane. D) 1,1-dichloro-2-ethylcyclopropane.

A) 1,1,1,3-tetrachloropentane.

Reaction of 1-hexene with NBS (N-bromosuccinimide) forms two isomeric bromohexenes, one of which is 3-bromo-1-hexene.Which of the following is the other isomer? A) 1-bromo-2-hexene. B) 6-bromo-1-hexene. C) 1-bromo-1-hexene. D) 2-bromo-1-hexene

A) 1-bromo-2-hexene.

There are four constitutional isomers having the formula C4H9Cl Which of the following would be a correct IUPAC name for one of these isomers? A) 1-chloro-2-methylpropane B) 3-chlorobutane C) 2-chloro-2-methylbutane D) 1-chloro-3-methylpropane

A) 1-chloro-2-methylpropane

Compound Z, C8H14, reacts with excess hydrogen and a Pt catalyst to give 2,5-dimethylhexane as the only product. Z diplay's three 13C nmr signals, all at higher field than 100 ppm, and does not absorb in the UV at wavelengths greater than 200 nm. Oxidation of Z by either ozone or potassium permanganate produces a single C4H8O2 carboxylic acid. Deduce the structure of Z. A) 2,5-dimethyl-3-hexyne B) trans-2,5-dimethyl-3-hexene C) cis-2,5-dimethyl-3-hexene D) 2,5-dimethyl-2,4-hexadiene

A) 2,5-dimethyl-3-hexyne

The IUPAC name for (CH3)2CHCH(CH3)CH2CH=CH2 is ... A) 4,5-dimethyl-1-hexene B) 4,5,5-trimethyl-1-pentene C) 2,3-dimethyl-5-hexene D) 4-methyl-4-isopropyl-1-butene

A) 4,5-dimethyl-1-hexene

Which of the following olefins would you expect to react most rapidly with concentrated sulphuric acid ? A) H2C=CH2 B) (CH3)2C=CH2 C) Cl2C=CCl2 D) CF3CH=CH2

B) (CH3)2C=CH2

Which of the following is not an electrophile? A) C2H5OC2H5 B) BF3 C) [CH3]3C(+) D) HOCl

A) C2H5OC2H5

What is the relative rate of addition of HBr to I: 1,3-pentadiene; II: 1,4-pentadiene; and III: 1-pentyne? ' A) I > II > III. B) III > II > I. C) II > I > III. D) III > I > II.

A) I > II > III.

Which of the following dimethylcyclobutanes is chiral ? A) trans-1,2-dimethylcyclobutane B) cis-1,2-dimethylcyclobutane C) trans-1,3-dimethylcyclobutane D) cis-1,3-dimethylcyclobutane

A) trans-1,2-dimethylcyclobutane

A C8H14 hydrocarbon (X) is reduced by sodium in liquid ammonia to a single C8H16 product (Y).Both of these compounds undergo hydrogenation (Pt catalyst) to give 2,5-dimethylhexane.Ozonolysis of Y with an oxidative workup produces a single C4H8O2 carboxylic acid.Reaction of Y with perbenzoic acid (C6H5CO3H) gives a chiral C8H14O product, but reaction with bromine gives an achiral C8H14Br2 product. What are X and Y? A) X is 2,5-dimethyl-3-hexyne ; Y is cis-2,5-dimethyl-3-hexene. B) X is 2,5-dimethyl-3-hexyne ; Y is trans-2,5-dimethyl-3-hexene. C) X is 2.5-dimethyl-1,5-hexadiene ; Y is 2,5-dimethyl-3-hexyne. D) X is 2,5-dimethyl-2,4-hexadiene ; Y is cis-2,5-dimethyl-3-hexene.

B) X is 2,5-dimethyl-3-hexyne ; Y is trans-2,5-dimethyl-3-hexene.

The preferred conformation of cis-1,3-dimethylcyclohexane is ... A) chair--diaxial B) chair--diequatorial C) chair--one axial / one equatorial D) boat--mixed orientations

B) chair--diequatorial

Two C5H8 isomers undergo catalytic (Pt) hydrogenation to form the same C5H10 product. On ozonolysis followed by oxidative workup (H2O2), one isomer gave a C5H8O4 diacid, while the other isomer gave a C5H8O3 ketoacid.Which of the following isomeric pairs correspond to this evidence? A) cyclopentene and 1-pentyne B) cyclopentene and 1-methylcyclobutene C) 1-methylcyclobutene and 3-methylcyclobutene D) cyclopentene and 3-methylcyclobutene

B) cyclopentene and 1-methylcyclobutene

wo C4H6 isomers give the same C4H8O product from HgSO4 catalyzed hydration in aqueous acid. However, these isomers give different C4H6Br4 products with excess bromine. What are these isomeric hydrocarbons? A) cyclobutene and methylenecyclopropane B) 1,2-butadiene and 1,3-butadiene C) 1-butyne and 2-butyne D) 2-butyne and cyclobutene

C) 1-butyne and 2-butyne

A C6H10 hydrocarbon forms an insoluble silver salt when treated with silver nitrate in ethanolic ammonia.Acid catalyzed hydration with a HgSO4 catalyst generates a single C6H12O ketone, and pemanganate oxidation yields a C5H10O2 carboxylic acidThis compound is most likely which of the following? A) cyclohexene. B) methylenecyclopentane. C) 1-hexyne. D) 3-hexyne.

C) 1-hexyne.

Limiting your answer to cycloalkanes and ignoring stereoisomers, how many C6H12 constitutional isomers are there? A) 6 B) 9 C) 12 D) 13

C) 12

What is the IUPAC name for CH3CH2C(CH3)2CH2CH(CH3)2? A) 3,3,5-trimethylhexane B) 2,2,5-trimethylhexane C) 2,4,4-trimethylhexane D) 1,1,3,3-tetramethylpentane

C) 2,4,4-trimethylhexane

The alkane CH3CH2C(CH3)2CH2CH(CH3)2 has how many 1º, 2º. 3º & 4º carbon atoms? 1º2º3º4º A) 4 2 2 1 B) 5 1 2 1 C) 5 2 1 1 D) 6 1 1 1

C) 5 2 1 1

The product from bromine addition to trans-2-butene will be ... A) optically active B) racemic C) a meso compound D) chiral

C) a meso compound

Which one of the following compounds contains the greatest number of sp2 hybridized carbon atoms? A) 1,4-Cycloheptadiene B) 2,5-dimethyl-2,3,4-hexatriene C) Phenylacetylene D) 1,1-diallyl-3,3-divinylcyclobutane

D) 1,1-diallyl-3,3-divinylcyclobutane

Which one of the following compounds contains the greatest number of sp3 hybridized carbon atoms? A) 1,4-Cyclooctadiene B) 2,5-dimethyl-2,3,4-hexatriene C) Phenylacetylene D) 1,1-diallyl-3,3-divinylcyclobutane

D) 1,1-diallyl-3,3-divinylcyclobutane

Reaction of 1,1-dibromopentane with three equivalents of NaNH2 in ether is followed by treatment with 0.1M HCl at 0º C.What is the product? A) cyclopentene. B) 1,2-pentadiene. C) 2-pentyne. D) 1-pentyne.

D) 1-pentyne.

A C6H12 compound reacts with ozone to yield a single C3H6O product. Gas phase free radical bromination of the hydrocarbon gives a single C6H11Br product. A likely identification of this compound is .. A) cyclohexane B) cyclohexene C) 3-hexene D) 2,3-dimethyl-2-butene

D) 2,3-dimethyl-2-butene

Which isomer of hexane has only two different sets of structurally equivalent hydrogen atoms.? A) 2,2-dimethylbutane B) 2-methylpentane C) 3-methylpentane D) 2,3-dimethylbutane

D) 2,3-dimethylbutane

Which of the following isomeric hexenes will have the smallest heat of hydrogenation? A) 4-methyl-1-pentene. B) (E)-4-methyl-2-pentene. C) (Z)-4-methyl-2-pentene. D) 2-methyl-2-pentene.

D) 2-methyl-2-pentene.

A chiral C6H12 hydrocarbon undergoes catalytic hydrogenation to yield an achiral C6H14 product. What is the starting compound? A) cis-2-hexene B) 3-methyl-2-pentene C) 4-methyl-2-pentene D) 3-methyl-1-pentene

D) 3-methyl-1-pentene

Considering that the angles of a regular pentagon are 108º, why is cyclopentane not planar? A) all the carbons are sp2 hybridized, so there is considerable angle strain. B) The C-C bonds are formed by overlap of p-orbitals, so the 90º angle results in large angle strain. C) The cyclic overlap of bonding orbitals results in anti-aromaticity destabilization. D) The five C-C bonds have eclipsing strain.

D) The five C-C bonds have eclipsing strain.

What structural change takes place when an alkene undergoes a Simmons-Smith reaction? A) addition of ethene gives a cyclobutane derivative. B) the double bond is shifted to a more substituted location. C) the double bond is converted to a triple bond. D) a methylene group is added to give a cyclopropane derivative.

D) a methylene group is added to give a cyclopropane derivative.

A tertiary carbocation (carbonium ion) is more stable than either a secondary or primary carbocation because ... A) it carries three positive charges B) it has a pyramidal configuration C) it has a trigonal planar configuration D) it possesses three electron-donating substituent groups

D) it possesses three electron-donating substituent groups

Treatment of 1-methylcyclohexene with an ether solution of diborane ( B2H6 ), followed by reaction with alkaline H2O2 produces what product? A) 1-methylcyclohexanol B) cis-1-methylcyclohexane-1,2-diol C) cis-2-methylcyclohexanol D) trans-2-methylcyclohexanol

D) trans-2-methylcyclohexanol