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Chapter 9 Multiple Choice Questions: Topic: Addition Reaction Mechanisms Section: 9.1 Difficulty Level: Easy 1.

In an addition reaction to an alkene, the π bond plays the role of: A) nucleophile B) electrophile C) leaving group D) A and B E) B and C Ans: A

Topic: Addition Reaction Mechanisms Section: 9.1 Difficulty Level: Moderate 2.

Addition reactions of alkenes are characterized by: A) formation of a π bond B) addition of two groups across a double bond C) breaking of a π bond D) A and B E) B and C Ans: E

Topic: Addition vs. Elimination Thermodynamic Perspective Section: 9.2 Difficulty Level: Easy 3.

The decrease in entropy (the S value is negative) observed for alkene addition reactions results from: A) the breaking of a π and  bond. B) the formation of two  bonds. C) the reaction being exothermic. D) two molecules reacting to form a single molecule. E) the temperature dependence of the S term. Ans: D

Topic: Addition vs. Elimination Thermodynamic Perspective Section: 9.2 Difficulty Level: Easy 4.

In a reaction where addition and elimination reactions are in competition, which of the following statements is most correct? A) Addition and elimination reactions are favored at low temperatures. B) Addition and elimination reactions are favored at high temperatures. C) Only addition reactions are favored at low temperatures. D) Only elimination reactions are favored at low temperatures. E) Addition and elimination reactions are disfavored at low temperatures. Ans: C

Topic: Addition vs. Elimination Thermodynamic Perspective Section: 9.2 Difficulty Level: Easy 5.

Which statement is true about the temperature dependence of an addition reaction? A) Addition reactions are thermodynamically favorable at all temperatures. B) Addition reactions are thermodynamically disfavored at all temperatures. C) Addition reactions are thermodynamically favorable at low temperatures. D) Addition reactions are thermodynamically favorable at high temperatures. E) Addition reactions are thermodynamically impossible. Ans: C

Topic: Addition vs. Elimination Thermodynamic Perspective Section: 9.2 Difficulty Level: Moderate 6.

For an addition reaction, why does the free energy term, G, become more positive with increasing temperature? A) The positive entropy term dominates at high temperature. B) The negative entropy term dominates at high temperature. C) The positive enthalpy term dominates at high temperature. D) The negative enthalpy term dominates at high temperature. E) The enthalpy and entropy terms cancel at high temperature. Ans: A

Topic: Addition vs. Elimination Thermodynamic Perspective Section: 9.2 Difficulty Level: Hard 7.

Addition reactions are favorable at low temperatures because: A) the positive enthalpy term is larger than the negative entropy term. B) the negative enthalpy term is larger than the positive entropy term. C) the positive enthalpy term is smaller than the negative entropy term. D) the negative enthalpy term is smaller than the positive entropy term. E) the enthalpy and entropy terms are equal. Ans: B

Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Easy 8.

Which of the molecules below would be the expected product for hydrohalogenation of the following alkene:

A) B) C) D) E) Ans:

E

Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Easy 9.

In the addition reaction of HI to 2-methyl-2-butene, the Markovnikov addition mechanism involves: A) attack of 2-methyl-2-butene initiated by an iodide ion. B) attack of 2-methyl-2-butene initiated by an iodine atom. C) isomerization of 2-iodo-2-methylbutene. D) formation of a carbocation at carbon two (C-2). E) formation of carbocation at carbon three (C-3). Ans: D

Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Easy 10.

The expected Markovnikov addition product of HI to 2-methyl-2-butene is: A) 2-iodopentane B) 2-iodo-2-methylbutane C) 1-iodo-2-methylbutane D) 2-iodo-1-methylbutane E) 3-iodo-2-methylbutane

Ans: B Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Easy 11.

The regioselectivity and stereospecificity in hydrohalogenation of an alkene is best described as: A) Markovnikov orientation with syn-addition B) Markovnikov orientation with anti-addition C) anti-Markovnikov orientation with syn-addition D) anti-Markovnikov orientation with anti-addition E) Markonikov orientation with both syn- and anti-addition Ans: E

Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Easy 12.

Which of the structures shown depicts the most stable carbocation intermediate formed in a hydrohalogenation reaction?

A) B) C) D) E) Ans:

I II III IV V B

Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Easy 13.

What compound is the expected product upon Markovnikov hydrohalogenation with HBr of the alkene shown below?

A) B)

C) D) E) Ans:

B

Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Easy 14.

The expected major product of the following reaction is:

A)

B) C) D)

E) Ans:

C

Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Easy 15.

The expected major product of the following reaction is:

A) B)

C) D) E) Ans:

A

Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Easy 16.

What is the expected major product for the following reaction?

A) B) C) D) E) Ans:

I II III IV V D

Topic: Anti-Markovnikov Hydrohalogenation Section: 9.3 Difficulty Level: Easy 17.

Which of the molecules below arises from anti-Markovnikov hydrohalogenation with HBr of the alkene shown?

A)

B) C)

D) E) Ans:

C

Topic: Stereochemistry of Hydrohalogenation Section: 9.3 Difficulty Level: Easy 18.

Which of the alkenes shown below would produce a chirality center upon hydrohalogenation?

A) B) C) D)

E) Ans:

B

Topic: Stereochemistry of Hydrohalogenation Section: 9.3 Difficulty Level: Easy 19.

What is the major product for the following reaction?

A)

B)

C)

D) E) Ans:

A

Topic: Stereochemistry of Hydrohalogenation Section: 9.3 Difficulty Level: Moderate 20.

Which of the alkenes below would be expected to produce a chirality center upon hydrohalogenation in the presence of peroxide? A) B) C) D) E) Ans:

B

Topic: Hydrohalogenation Section: 9.3 Difficulty Level: Moderate 21.

Which of the given reaction schemes would produce the molecule shown below?

A) B) C) D) E) Ans:

Both A and B Both B and C E

Topic: Stereochemistry of Hydrohalogenation Section: 9.3 Difficulty Level: Moderate 22.

Which of the molecules below are enantiomers, formed as products upon reaction of HBr with 4-methylpent-1-ene?

A) B) C) D) E) Ans:

I and II II and III III and IV I and III II and IV E

Topic: Hydrohalogenation and Carbocation Rearrangements Section: 9.3 Difficulty Level: Moderate 23.

Which of the following carbocations is likely to undergo rearrangement through a methyl shift?

A) B) C) D) E) Ans:

I II III I and II II and III D

Topic: Hydrohalogenation and Carbocation Rearrangements Section: 9.3 Difficulty Level: Moderate 24.

Which of the following carbocations is likely to undergo rearrangement through a hydride shift?

A) B) C) D) E) Ans:

I II III I and II II and III D

Topic: Hydrohalogenation and Carbocation Rearrangements Section: 9.3 Difficulty Level: Moderate 25.

The expected major product(s) of HCl addition to the alkene shown would be:

A) B) C) D) E) Ans:

I and II II and III I and IV V All of the above are equally likely to form A

Topic: Hydrohalogenation and Carbocation Rearrangements Section: 9.3 Difficulty Level: Moderate 26.

The expected major product(s) of HBr addition to the alkene shown would be:

A)

B)

C) D) E) Ans:

A

Topic: Stereochemistry of Hydrohalogenation and Carbocation Rearrangements Section: 9.3 Difficulty Level: Moderate 27.

The reaction shown below would be expected to produce as major products which of the following compounds?

A)

B)

C)

D)

E) Ans:

D

Topic: Hydrohalogenation and Carbocation Rearrangements Section: 9.3 Difficulty Level: Hard 28.

What is the IUPAC name of the expected major product formed upon reaction of HCl with 3-methyl-1-butene? A) 1-Chloro-2-methylbutane B) 1-Chloro-3-methylbutane C) 2-Chloro-2-methylbutane D) 2-Chloro-3-methylbutane E) 1-Chloropentane Ans: C

Topic: Hydrohalogenation and Carbocation Rearrangements Section: 9.3 Difficulty Level: Hard 29.

Select the expected major product(s) of the following reaction:

A)

B) C) D) E) Ans:

A and B A and C C

Topic: Hydrohalogenation and Carbocation Rearrangements Section: 9.3 Difficulty Level: Hard 30.

Identify the expected product(s) for the reaction shown below?

A) B)

C)

D)

E) Ans:

C

Topic: Acid Catalyzed Hydration Section: 9.4 Difficulty Level: Easy 31.

The regioselectivity and stereospecificity in the acid-catalyzed hydration of an alkene is best described as: A) Markovnikov orientation with syn-addition B) Markovnikov orientation with anti-addition C) anti-Markovnikov orientation with syn-addition D) anti-Markovnikov orientation with anti-addition E) Markonikov orientation with both syn- and anti-addition Ans: E

Topic: Acid Catalyzed Hydration Section: 9.4 Difficulty Level: Easy 32.

The expected major product of the following reaction is:

A) B) C) D) E) Ans:

I II III IV V D

Topic: Acid Catalyzed Hydration Section: 9.4 Difficulty Level: Easy 33.

The expected major product of the following reaction is:

A) B) C) D) E) Ans:

I II III IV V C

Topic: Acid Catalyzed Hydration Section: 9.4 Difficulty Level: Easy 34.

The expected major product of the following reaction is:

A)

B)

C)

D)

E)

Ans: D Topic: Acid Catalyzed Hydration Section: 9.4 Difficulty Level: Easy 35.

Treatment of 1-methylcyclohexene with H 3O+ would be expected to yield as the major product which of the molecules below?

A) B) C) D) E) Ans:

I and III II III and V IV I, III and V D

Topic: Acid Catalyzed Hydration Section: 9.4 Difficulty Level: Moderate 36.

Treatment of (S)-6-chloro-1-methyl-1-cyclohexene with H 3O+ is expected to produce which of the following?

A) B) C) D) E) Ans:

I and III II III and V IV I, III and V B

Topic: Acid Catalyzed Hydration Section: 9.4 Difficulty Level: Hard 37.

What is the expected major product for the following reaction?

A)

B)

C)

D)

E) Ans:

A

Topic: Oxymercuration-Demercuration Section: 9.5 Difficulty Level: Easy 38.

The regioselectivity and stereospecificity in the oxymercuration-demercuration of an alkene is best described as: A) Markovnikov orientation with syn-addition B) Markovnikov orientation with anti-addition C) anti-Markovnikov orientation with syn-addition D) anti-Markovnikov orientation with anti-addition E) Markonikov orientation with both syn- and anti-addition Ans: B

Topic: Oxymercuration-Demercuration Section: 9.5 Difficulty Level: Easy 39.

What is the expected major product for the following reaction?

A)

B)

C) D)

E) Ans:

B

Topic: Oxymercuration-Demercuration Section: 9.5 Difficulty Level: Easy 40.

What synthetic goal is achieved by subjecting an alkene to an oxymercurationdemercuration reaction sequence? A) Markovnikov addition of H2O, promoting skeletal rearrangement B) Markovnikov addition of H2O, preventing skeletal rearrangement C) anti-Markovnikov addition of H2O, promoting skeletal rearrangement D) anti-Markovnikov addition of H2O, preventing skeletal rearrangement E) anti-Markovnikov addition of H2O, syn-hydroxylation Ans: B

Topic: Oxymercuration-Demercuration Section: 9.5 Difficulty Level: Easy 41.

What is the expected major product for the following reaction?

A)

B)

C)

D)

E) Ans:

C

Topic: Oxymercuration-Demercuration Section: 9.5 Difficulty Level: Easy 42.

What is the expected major product for the following reaction?

A)

B)

C)

D)

E) Ans:

D

Topic: Oxymercuration-Demercuration Section: 9.5 Difficulty Level: Easy 43.

What is the expected major product for the following reaction?

A)

B)

C)

D)

E) Ans:

B

Topic: Oxymercuration-Demercuration Section: 9.5 Difficulty Level: Moderate 44.

When an alkene is subjected to treatment with Hg(OAc)2 in alcohol, followed by reaction with NaBH4, what functional group is formed? A) ether B) epoxide C) alkane D) syn diol E) alkyne Ans: A

Topic: Hydroboration-Oxidation Section: 9.6 Difficulty Level: Easy 45.

The regioselectivity and stereospecificity in the hydroboration-oxidation of an alkene is best described as: A) Markovnikov orientation with syn-addition B) Markovnikov orientation with anti-addition C) Anti-Markovnikov orientation with syn-addition D) Anti-Markovnikov orientation with anti-addition E) Markovnikov orientation with both syn- and anti-addition Ans: C

Topic: Hydroboration-Oxidation Section: 9.6 Difficulty Level: Easy 46.

What reagents are needed to accomplish the following transformation?

A) H2O/H+ B) H2O/Peroxide C) OH– D) BH3 E) 1. BH3, 2. HO–, H2O2, H2O Ans: E

Topic: Hydroboration-Oxidation Section: 9.6 Difficulty Level: Easy 47.

What is the expected major product for the following reaction sequence?

A) B) C) D) E) Ans:

E

Topic: Hydroboration-Oxidation Section: 9.6 Difficulty Level: Easy 48.

What is the expected major product for the following reaction sequence?

A) B) C) D) E) Ans:

I II III I and II I and III E

Topic: Hydroboration-Oxidation Section: 9.6 Difficulty Level: Moderate 49.

What is the expected major product for the following reaction sequence?

A)

B)

C)

D)

E) Ans:

E

Topic: Hydroboration-Oxidation Section: 9.6 Difficulty Level: Moderate 50.

What is the expected major product for the following reaction sequence?

A) B) C) D) E) Ans:

I II III IV V D

Topic: Hydroboration-Oxidation Section: 9.6 Difficulty Level: Moderate 51.

What is the expected major product for the following reaction sequence?

A) B)

C) D)

E)

Ans:

B

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 52.

What is the expected major product for the hydrogenation of an alkene? A) dihaloalkane B) alkane C) haloalkane D) alcohol E) ether Ans: B

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 53.

Provide the major organic product(s) for the reaction shown below.

A) B)

C) D) E) Ans:

B

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 54.

What product is formed when 5-chloro-1-methylcyclohexene is reduced with a Pt catalyst and H2? A) 1-chloro-5-methylcyclohexane B) 1-chloro-3-methylcyclohexane C) 5-chloro-1-methylcyclohexane D) 3-chloro-1-methylcyclohexane E) None of the above

Ans: B Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 55.

What product is formed when trans-1,2-dimethylcyclohexane is reacted with Pd/C and H2? A) No reaction B) cis-1,2-dimethylcyclohexane C) trans-3,4-dimethylhexane D) trans-1,2-dimethylhexane E) None of the above Ans: A

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 56.

Which of the following reagents accomplishes the transformation shown below?

A) B) C) D) E) Ans:

H2/HCl H2/H2SO4 H2/Ni H2O/Ni H2O/H2SO4 C

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 57.

Which of the reagents below are expected to convert cyclopentene into cyclopentane? A) H2 and Ni B) H2O C) Heat D) Zn, H3O+ E) Light Ans: A

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 58.

Which alkene would yield 3-methylpentane upon subjection to catalytic hydrogenation?

A) B) C) D) E) Ans:

I II III IV V B

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 59.

How many moles of hydrogen (H2) are consumed in the catalytic reduction of 1 mole of 1,3-dibromocyclohexa-1,4-diene? A) 1 B) 2 C) 3 D) 4 E) None of the above Ans: B 2

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 60.

How many moles of hydrogen (H2) are required to completely reduce 1 mole of cis2,3,3-trimethylhepta-1,5-diene? A) 0 B) 1 C) 2 D) 3 E) 4 Ans: C 2

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 61.

Which of the catalysts listed are used in the homogenous catalytic hydrogenation of alkenes? I) Ni II) Pt III) Wilkinson A) B) C) D) E) Ans:

I II III I and II II and III C

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 62.

In conducting a catalytic hydrogenation of an alkene, which catalyst listed is most likely soluble in the reaction medium? A) Ni B) Pt C) Pd D) Wilkinson E) All of the above are soluble Ans: D

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 63.

Wilkinson’s catalyst accomplishes which of the listed molecular transformations? A) syn addition of H2 to an alkene B) anti addition of H2 to an alkene C) syn dihydroxylation of an alkene D) anti dihydroxylation of an alkene E) oxidative cleavage of an alkene Ans: A

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Easy 64.

For the catalytic hydrogenation of alkenes, select from below those most likely to function as a homogenous catalyst? A) Wilkinson B) Ni C) Pd D) Pt E) Au Ans: A

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Moderate 65.

Which of the following will yield 2-methylpentane upon catalytic hydrogenation? A) 2-methyl-1-pentene B) 2-methyl-2-pentene C) 4-methyl-2-pentene D) 4-methyl-1-pentene E) All of the above Ans: E 2

Topic: Catalytic Hydrogenation Section: 9.7 Difficulty Level: Moderate 66.

For the complete reduction of 1 mole of (3E,5E)-hepta-1,3,5-triene with H2 using a Pd catalyst, how many moles of H2 are consumed? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: C

Topic: Catalytic Hydrogenation and Stereospecific...