Deck 7: Alkenes and Alkynes I

Question 1

Name the following compound:

A)(cis)-3-methoxyhex-3-ene
B)(Z)-4-methoxyhex-4-ene
C)(Z)-3-methoxyhex-3-ene
D)(E)-3-methoxyhex-3-ene
E)3-methoxyhex-3-ene

Answer 1

(Z)-3-methoxyhex-3-ene

Question 2

Name the following compound:

A)(R,Z)-5-phenyloct-5-en-3-ol
B)(R,Z)-5-benzyloct-5-en-3-ol
C)(R,E)-5-phenyloct-5-en-3-ol
D)(R,E)-5-benzyloct-5-en-3-ol
E)(R,E)-5-benzyloct-3-en-6-ol

Answer 2

(R,Z)-5-benzyloct-5-en-3-ol

Question 3

Name the following compound:

A)(S,E)-2,4-dibromo-3-methylpent-2-ene
B)(R,Z)-2,4-dibromo-3-methylpent-2-ene
C)(R,E)-2,4-dibromo-3-methylpent-3-ene
D)(S,E)-2,4-dibromo-3-methylpent-3-ene
E)(R,E)-2,4-dibromo-3-methylpent-2-ene

Answer 3

(R,E)-2,4-dibromo-3-methylpent-2-ene

Question 4

Which alkene would liberate the most heat per mole when subjected to catalytic hydrogenation?

A)
B)
C)
D)
E)

Question 5

Which structure represents (R,Z)-5-methylhept-2-ene?

A)
B)
C)
D)
E)None of these choices.

Question 6

A correct IUPAC name for the following compound is:

A)3,3,5-trimethyl-2-hexene
B)3-isobutyl-3-isopropyl-2-propene
C)3-isobutyl-4-methyl-2-pentene
D)3-(1-methylethyl)-5-methyl-2-hexene
E)None of these choices.

Question 7

Heats of hydrogenation data would be useful in comparing the relative stabilities of which of the following substances?

A)I,II,III
B)III,IV
C)I,II,V
D)Heats of hydrogenation data would not be a useful way to compare relative stabilities of any of the substances.
E)All of these substances could effectively be compared using heats of hydrogenation data.

Question 8

The correct IUPAC name for the following compound is:

A)4,5-Dimethyl-3-propyl-2-hexene
B)4,5-Dimethyl-3-propyl-1-hexene
C)3-(2,3-Dimethylpropyl)-1-hexene
D)2,3-Dimethyl-4-isopropyl-5-hexene
E)2,3-Dimethyl-4-propyl-5-hexene

Question 9

Name the following compound:

A)(S,E)-3-methyl-5-phenyl-3-heptene
B)(R,E)-3-methyl-5-phenyl-3-heptene
C)(S,E)-3-methyl-5-benzyl-3-heptene
D)(S,Z)-3-methyl-5-phenyl-3-heptene
E)(R,Z)-3-methyl-5-phenyl-3-heptene

Question 10

Which molecule would have the lowest heat of hydrogenation?

A)I
B)II
C)III
D)IV
E)V

Question 11

The correct IUPAC name for the following compound is:

A)2-Bromo-4-methylenehexane
B)2-(2-Bromopropyl)-1-butene
C)4-Bromo-2-ethyl-1-pentene
D)2-Bromo-4-ethyl-1-pentene
E)2-Bromo-4-ethyl-4-pentene

Question 12

Which structure represents (Z)-1,4-dichlorohex-3-en-1-yne?

A)
B)
C)
D)
E)None of these choices.

Question 13

Which structure represents (E)-1-bromo-2-methylhex-2-ene?

A)
B)
C)
D)
E)None of these choices.

Question 14

Name the following compound:

A)(S,Z)-3-bromo-4-methylhex-2-ene
B)(S)-3-bromo-4-methylhex-2-ene
C)(S,Z)-4-bromo-3-methylhex-4-ene
D)(S,E)-3-bromo-4-methylhex-2-ene
E)(R,E)-3-bromo-4-methylhex-2-ene

Question 15

The correct IUPAC name for the following compound is:

A)(E)-2-Bromo-3-chloro-5-methyl-2-hexene
B)(E)-2-Bromo-3-chloro-5-methyl-3-hexene
C)(Z)-2-Bromo-3-chloro-5-methyl-3-hexene
D)(Z)-2-Bromo-3-chloro-5-methyl-2-hexene
E)(E)-2-Methyl-5-bromo-4-chloro-4-hexene

Question 16

Name the following compound:

A)(E)-4-phenyl-4-methylbut-3-en-1-ol
B)(E)-4-phenylpent-3-en-1-ol
C)(Z)-4-phenylpent-3-en-1-ol
D)(Z)-4-phenyl-4-methylbut-3-en-1-ol
E)(E)-4-benzylpent-3-en-1-ol

Question 17

Name the following compound:

A)(S,E)-3-chlorohex-4-en-1-yne
B)(R,E)-3-chlorohex-2-en-5-yne
C)(S,E)-3-chlorohex-2-en-5-yne
D)(R,E)-3-chlorohex-4-en-1-yne
E)(R,E)-3-chloropent-4-en-1-yne

Question 18

Name the following compound:

A)(Z)-5-methylhex-4-en-2-yn-6-ol
B)(E)-5-methylhex-4-en-2-yn-6-ol
C)(E)-2-methylhex-2-en-4-yn-1-ol
D)(Z)-2-methylhex-2-en-4-yn-1-ol
E)(Z)-1-methylhex-2-en-3-yn-1-ol

Question 19

Which structure represents (Z)-4-bromohexa-1,3-diene?

A)
B)
C)
D)
E)None of these choices.

Question 20

Select the structure of 4-ethyl-2,3-dimethyl-2-heptene.

A)
B)
C)
D)
E)

Question 21

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 22

Dehydrohalogenation of tert-pentyl bromide at higher temperatures will produce 2-methyl-1-butene as the chief product when:

A)CH₃COONa is employed as the base.
B)KOH/C₂H₅OH is employed as the base
C)CH₃CH₂ONa/CH₃CH₂OH is employed as the base.
D)(CH₃)₃COK/(CH₃)₃COH is employed as the base.
E)any base is used,as long as the temperature is sufficiently high.

Question 23

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 24

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 25

What is the major product for the following reaction?

A)
B)
C)
D)
E)None of these choices.

Question 26

Concerning the relative stabilities of alkenes,which is a false statement?

A)Unless hydrogenation of the alkenes gives the same alkane,heats of hydrogenation cannot be used to measure their relative stabilities.
B)In general,the greater the number of alkyl groups attached to the carbon atoms of the double bond,the greater the stability of the alkene.
C)The greater the quantity of heat liberated on combustion or hydrogenation of an alkene,the greater its energy content.
D)trans-Cycloalkenes are always more stable than the cis-isomers.
E)Heats of combustion can be used to measure the relative stabilities of isomeric alkenes,even though their hydrogenation products are not identical.

Question 27

Which compound listed below would you expect to be the major product when 2-bromo-2-methylbutane is refluxed with KOH/ethanol?

A)
B)
C)
D)
E)

Question 28

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 29

What is the major product for the following reaction?

A)
B)
C)
D)
E)More than one of these choices.

Question 30

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 31

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 32

Zaitsev's rule states that:

A)In electrophilic addition of an unsymmetrical reagent to an unsymmetrical alkene,the more positive portion of the reagent will become attached to the carbon of the double bond bearing the greater number of hydrogen atoms.
B)An equatorial substituent in cyclohexane results in a more stable conformation than if that substituent were axial.
C)E2 reactions occur only if the $\beta$ -hydrogen and leaving group can assume an anti-periplanar arrangement.
D)When a reaction forms an alkene,and several possibilities exist,the more (or most)stable isomer is the one which predominates.
E)The order of reactivity of alcohols in dehydration reactions is 3º > 2º > 1º.

Question 33

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 34

What is the major product for the following reaction?

A)
B)
C)
D)
E)None of these choices.

Question 35

Your task is to convert 2-bromobutane to 1-butene in highest yield.Which reagents would you use?

A)KOH/H₂O
B)KOH/CH₃OH
C)CH₃ONa/CH₃OH
D)CH₃CH₂ONa/CH₃CH₂OH
E)(CH₃)₃COK/(CH₃)₃COH

Question 36

Which product (or products)would be formed in appreciable amount(s)when trans-1-bromo-2-methylcyclohexane undergoes dehydrohalogenation upon treatment with sodium ethoxide in ethanol?

A)I
B)II
C)III
D)IV
E)More than one of these choices.

Question 37

What is the major product for the following reaction?

A)CH₃CH₂(CH₃)C=CHCH₃
B)CH₃CH₂(CH₃)CHCH=CH₂
C)CH₃CH₂(CH₃)CHCH(OCH₂CH₃)CH₃
D)None of these choices.
E)No reaction.

Question 38

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 39

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 40

Rank the following compounds from lowest to highest heat of hydrogenation:

A)I,II,III,IV
B)IV,III,II,I
C)II,III,IV,I
D)I,IV,III,II
E)none of these choices

Question 41

Regarding the use of potassium tert-butoxide as a base in E2 reactions,it is incorrect to state that:

A)this base is more effective than ethoxide ion,because it (KOt-Bu)is the more basic of the two.
B)it tends to give the anti-Zaitsev,i.e.,Hofmann,product.
C)it is more reactive in dimethyl sulfoxide than it is in tert-butyl alcohol.
D)it favors E2 reactions over competing S_N2 reactions.
E)it will form,predominantly,the more stable alkene.

Question 42

Which one of the following alcohols would dehydrate most rapidly when treated with sulfuric acid?

A)I
B)II
C)III
D)IV
E)V

Question 43

What is the major product of the reaction of the following reaction?

A)
B)
C)
D)
E)More than one of these choices.

Question 44

What is the major product of the reaction between methanol and (2R,3S)-2-bromo-3-methylpentane at room temperature?

A)
B)
C)
D)
E)Two of these choices.

Question 45

Which mechanistic step in the acid-catalyzed dehydration of 3,3-dimethyl-2-butanol is the rate determining step?

A)
B)
C)
D)
E)

Question 46

Rearrangements are likely to occur in which of the following reaction types?

A)S_N1 reactions
B)S_N2 reactions
C)E1 reactions
D)E2 reactions
E)Both S_N1 and E1 reactions

Question 47

Which alcohol would be most easily dehydrated?

A)I
B)II
C)III
D)IV
E)V

Question 48

Neopentyl alcohol,(CH₃)₃CCH₂OH,cannot be dehydrated to an alkene without rearrangement.What is the chief product of dehydration?

A)I
B)II
C)III
D)IV
E)V

Question 49

Which alcohol would initially produce the most stable carbocation when treated with concentrated H₂SO₄?

A)
B)
C)
D)
E)

Question 50

What are the major product(s)formed when trans-1-bromo-2-methylcyclohexane reacts with sodium isopropoxide in isopropanol?

A)I
B)II
C)I and II
D)III
E)III and IV

Question 51

What is the major product of the reaction,

A)(CH₃)₂C=C(CH₃)₂
B)(CH₃)₃C-CH=CH₂
C)(CH₃)₂C=CHCH₃
D)(CH₃)₂C=CHCH₂CH₃
E)None of these choices.

Question 52

Carbocations are frequent intermediates in acidic reactions of alkenes,alcohols,etc.What do carbocations usually do? They may:

A)rearrange to a more stable carbocation.
B)lose a proton to form an alkene.
C)combine with a nucleophile.
D)react with an alkene to form a larger carbocation.
E)do all of these choices.

Question 53

Which of the following carbocations would NOT be likely to undergo rearrangement?

A)
B)
C)
D)
E)

Question 54

Which statement(s)is/are true of acid-catalyzed alcohol dehydrations?

A)Protonation of the alcohol is a fast step.
B)Formation of a carbocation from the protonated alcohol is a slow step.
C)Rearrangements of less stable carbocations to more stable carbocations are common.
D)Loss of a proton by the carbocation intermediate is a fast step.
E)All of these choices.

Question 55

Which product(s)would be produced by acid-catalyzed dehydration of 2-methyl-2-pentanol?

A)
B)
C)
D)
E)

Question 56

What are the major product(s)formed when cis-1-bromo-2-methylcyclohexane reacts with sodium isopropoxide in isopropanol?

A)I
B)II
C)I and II
D)III
E)III and IV

Question 57

Which alcohol would be most easily dehydrated?

A)
B)
C)
D)
E)

Question 58

Which of the following alcohols would probably undergo dehydration using 25% sulfuric acid below 100 ^oC?

A)II,IV,V
B)I,II,III
C)III and IV
D)III,IV,V
E)all can be dehydrated

Question 59

What is the major product for the following reaction?

A)
B)
C)
D)
E)More than one of these choices.

Question 60

Which compound would be the major product?

A)
B)
C)
D)
E)

Question 61

What is the major product of the reaction of the following reaction?

A)
B)
C)
D)
E)None of these choices.

Question 62

What will be the major product of the following reaction?

A)
B)
C)
D)
E)

Question 63

Which reaction would not result in alkylation of the acetylide anion as the major products?

A)
B)
C)
D)
E)None of these choices.

Question 64

Which of the following methods could be used to synthesize 4,4-dimethyl-2-hexyne?

A)
B)
C)
D)More than one of these choices.
E)None of these choices.

Question 65

Which of the following reactions would yield 2-pentyne?

A)
B)
C)
D)
E)

Question 66

Which reaction would yield 2-butyne?

A)CH₃C $\equiv$ C:^-Na⁺ + CH₃Br $\to$
B)CH₃CH₂Br + HC $\equiv$ C:^-Na⁺ $\to$
C)CH₃:^-Na⁺ + HC $\equiv$ CCH₃ $\to$
D)More than one of these choices.
E)None of these choices.

Question 67

What is the major product for the following reaction?

A)
B)
C)
D)
E)None of these choices.

Question 68

Which reaction conditions would not yield 2-butyne from 1-propyne?

A)
B)
C)
D)
E)More than one of these choices.

Question 69

What is the major product(s)of the reaction of the following reaction sequence?

A)
B)
C)
D)
E)A mixture of two of these choices.

Question 70

A compound X with the formula C₇H₁₀ undergoes catalytic hydrogenation to produce a compound Y with the formula C₇H_14. What could be true of X?

A)X might have one triple bond and one ring.
B)X might have two double bonds and one ring.
C)X might have one double bond and two rings.
D)X might have one double bond and one triple bond.
E)More than one of these choices.

Question 71

What is the major product of the reaction of the following reaction?

A)
B)
C)
D)
E)

Question 72

An unknown compound,B,has the molecular formula C₇H₁₂.On catalytic hydrogenation 1 mol of B absorbs 2 mol of hydrogen and yields 2-methylhexane.B has significant IR absorption band at about 3300 and 2200 cm^-1.Which compound best represents B?

A)3-methyl-1-hexyne
B)5-methyl-2-hexyne
C)5-methyl-1,3-hexadiene
D)5-methyl-1-hexyne
E)2-methyl-1,5-hexadiene

Question 73

What is the major product of the reaction of the following reaction?

A)
B)
C)
D)
E)

Question 74

A compound,C₆H₁₀,which reacts with 2 mol of hydrogen over a platinum catalyst and which shows an IR absorption band at approximately 3300 cm^-1 could be:

A)I
B)II
C)III
D)IV
E)V

Question 75

What is the major product for the following reaction?

A)
B)
C)
D)
E)

Question 76

Which reaction would not primarily proceed via an S_N2 mechanism?

A)
B)
C)
D)
E)All of them proceed via S_N2

Question 77

Which would be the major product of the following reaction sequence?

A)
B)
C)
D)
E)None of these choices.

Question 78

Which of the following reactions would yield 3,3-dimethyl-1-butene in a reasonable percentage yield (i.e.,greater than 50%)?

A)
B)
C)

D)All of these choices.
E)Only two of these choices.

Question 79

Which statement is/are true about acetylide anions?

A)The alkylated product is poor with secondary alkyl halides.
B)Primary alkyl halides are best suited for alkylation.
C)In the presence of tertiary alkyl halides,the acetylide anion acts as base to give an elimination product.
D)Only two of these statements are true.
E)All of the statements are true.

Question 80

Which alkene would you expect to be the major product of the following dehydration?

A)I
B)II
C)III
D)IV
E)V