Deck 7: Alkenes and Alkynes I: Properties and Synthesis, Elimination Reactions of Alkyl Halides

Question 1

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Answer 1

Question 2

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 the above

Answer 2

None of the above

Question 3

Which alkene is most stable?

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

Answer 3

I

Question 4

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 5

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 the above
E) No reaction

Question 6

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 the above substances could effectively be compared using heats of hydrogenation data.

Question 7

What is the major product for the following reaction?

A)

B)

C)

D)

E) More than one of the above

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

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

Question 10

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Question 11

What is the major product for the following reaction?

A)

B)

C)

D)

E) None of the above

Question 12

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

A)

B)

C)

D)

E)

Question 13

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 14

What is the major product for the following reaction?

A)

B)

C)

D)

E) None of the above

Question 15

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 16

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Question 17

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

A)

B)

C)

D)

E)

Question 18

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 19

Which molecule would have the lowest heat of hydrogenation?

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

Question 20

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Question 21

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 (KO-t-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 22

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 23

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

A)

B)

C)

D)

E)

Question 24

Which alcohol would be most easily dehydrated?

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

Question 25

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Question 26

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

A)

B)

C)

D)

E)

Question 27

Which alcohol would be most easily dehydrated?

A)

B)

C)

D)

E)

Question 28

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 29

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Question 30

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 the above.

Question 31

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 is a fast step.
E) All of the above

Question 32

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Question 33

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

A)

B)

C)

D)

E)

Question 34

Which compound would be the major product?

A)

B)

C)

D)

E)

Question 35

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 36

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 37

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Question 38

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

Question 39

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Question 40

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 41

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

A)

B)

C)

D) More than one of these
E) None of these

Question 42

Which statement is/are true about acetylide anions?

A) They do not alkylate 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 the above are true.
E) All of the statements are true.

Question 43

What is the major product for the following reaction?

A)

B)

C)

D)

E)

Question 44

Which reaction would not primarily proceed via an S_N2 mechanism?

A)

B)

C)

D)

E) All of them proceed via S_N2

Question 45

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 46

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

A)

B)

C)

D)

E) None of the above

Question 47

Which reaction would yield 2-butyne?

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

Question 48

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

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

Question 49

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

A)

B)

C)

D)

E) More than one of these

Question 50

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 51

What is the major product for the following reaction?

A)

B)

C)

D)

E) None of the above

Question 52

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

A)

B)

C)

D)

E) More than one of the above

Question 53

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 the above

Question 54

What is the structure of a compound with formula C₆H₁₀ which has IR absorption at approximately 3300 cm^-1 and which can be catalytically reduced with hydrogen to 2-methylpentane?

A)

B)

C)

D)

E)

Question 55

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

A)

B)

C)

D)

E) None of the above

Question 56

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

A)

B)

C)

D)

E) None of the above

Question 57

What is the major product for the following reaction?

A)

B)

C)

D)

E) More than one of the above

Question 58

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 59

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

A)

B)

C)

D)

E)

Question 60

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

A)

B)

C)

D)

E)

Question 61

Given: One can conclude that X has:

A) no rings and no double bonds.
B) no rings and one double bond.
C) one ring and one double bond.
D) two rings and no double bonds.
E) one triple bond.

Question 62

What is the major product for the following reaction sequence?

A)

B)

C)

D)

E)

Question 63

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

A) (CH₃CH₂)₂C=C=CHT
B) (CH₃CH₂)₂C=C=CH₂
C) (CH₃CH₂)₂CHCCT
D) (CH₃CH₂)₂CHCH=CHT
E) None of the above

Question 64

On hydrogenation,a compound C₉H₁₂ absorbs 2 mol of hydrogen.Which of the following is a possible structure for the compound?

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

Question 65

What is the major product for the following reaction sequence?

A)

B)

C)

D)

E) None of the above

Question 66

What is the major product for the following reaction sequence?

A)

B)

C)

D)

E) None of the above

Question 67

What is the major product for the following reaction sequence?

A)

B)

C)

D)

E) None of the above

Question 68

Which would be the major product of the following reaction?

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

Question 69

What is the major product for the following reaction sequence?

A)

B)

C)

D)

E) None of the above

Question 70

Which of these is the most satisfactory method for the preparation of cis-2-pentene?

A) CH₃CHBrCH₂CH₂CH₃ + (CH₃)₃COK/(CH₃)₃COH
B) CH₃C $\equiv$ CCH₂CH₃ + H₂,Pt
C) CH₃C $\equiv$ CCH₂CH₃ + H₂,Ni₂B (P-2)
D) CH₃C $\equiv$ CH₂CH₃ + Li/liq.NH₃
E) CH₃CH₂CHBrCH₂CH₃ + CH₃CH₂ONa/CH₃CH₂OH

Question 71

What is the major product for the following reaction sequence?

A)

B)

C)

D)

E) None of the above

Question 72

What is the major product for the following reaction sequence?

A)

B)

C)

D)

E) None of the above

Question 73

What is the major product for the following reaction sequence?

A)

B)

C)

D)

E) None of the above

Question 74

Which reaction would not be a method for preparing 5-methyl-1-hexyne?

A)

B)

C)

D)

E)

Question 75

The structure of the product,C,of the following sequence of reactions would be:

A)

B)

C)

D)

E)

Question 76

Upon catalytic hydrogenation,a compound C₆H₆ absorbs four moles of hydrogen.Select a structure for C₆H₆.

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

Question 77

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

A)

B)

C)

D)

E)

Question 78

What is the major product for the following reaction sequence?

A)

B)

C)

D)

E) None of the above

Question 79

Which is not a satisfactory procedure for the synthesis of 3-methyl-1-butene?

A) (CH₃)₂CHCHOCH₃ + conc.H₂SO₄
B) (CH₃)₂CHC $\equiv$ CH + Li/liq.NH₃
C) (CH₃)₂CHCH₂CH₂Br + CH₃ONa/CH₃OH
D) (CH₃)₂CHCHBrCH₃ + (CH₃)₃COK/(CH₃)₃COH
E) (CH₃)₂CHC $\equiv$ CH + H₂/Ni₂B (P-2)

Question 80

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

A)

B)

C)

D)

E) None of the above