Chapter 6 Flashcards
1
Q
Which of the following best describes the carbon-chlorine bond of an alkyl chloride?
A) nonpolar; no dipole
B) polar; d+ at carbon and d- at chlorine
C) polar; d- at carbon and d+ at chlorine
D) ionic
E) none of the above
A
B) polar; d+ at carbon and d- at chlorine
2
Q
Which of the following is classified as a vinylic halide? A) CH3CH=CHOH B) CH3CH=CHCl C) CH3CH=CHCH2Cl D) CH3CH2CH2CH2Br E) BrCH2CH=CH2
A
B) CH3CH=CHCl
3
Q
Which of the following is a secondary halide? A) ClCH2CH2C(CH3)3 B) ClCH2CH2CH(CH3)2 C) (CH3)2CClCH2CH3 D) (CH3)3CCHClCH3 E) ClCH2C(CH3)CH2CH3
A
D) (CH3)3CCHClCH3
4
Q
Which of the following is a tertiary halide? A) ClCH2CH2C(CH3)3 B) ClCH2CH2CH(CH3)2 C) (CH3)2CClCH2CH3 D) (CH3)3CCHClCH3 E) ClCH2C(CH3)CH2CH3
A
C) (CH3)2CClCH2CH3
5
Q
Which of the following is a geminal dihalide? A) cis-1,2-dibromocyclopentane B) 3,3-dichloropentane C) trans-1,4-diiodocyclohexane D) isobutyl chloride E) 1,3-dibromoheptane
A
B) 3,3-dichloropentane
6
Q
Which of the following is a vicinal dihalide? A) cis-1,2-dibromocyclopentane B) 3,3-dichloropentane C) trans-1,4-diiodocyclohexane D) isobutyl chloride E) 1,3-dibromoheptane
A
A) cis-1,2-dibromocyclopentane
7
Q
Which of the following is a secondary alkyl halide? A) methyl bromide B) isopropyl chloride C) t-butyl iodide D) propyl bromide E) isobutyl chloride
A
B) isopropyl chloride
8
Q
Which of the following is a primary alkyl halide? A) methyl bromide B) isopropyl bromide C) t-butyl iodide D) cyclohexyl bromide E) isobutyl chloride
A
E) isobutyl chloride
9
Q
Which of the following best describes DDT?
A) a chlorocarbon used to decaffeinate coffee beans
B) a polybrominated organic compound used as a herbicide
C) a Freon used as a foaming agent
D) a mixed alkyl halide used as an anesthetic
E) a polychlorinated organic compound used as an insecticide
A
E) a polychlorinated organic compound used as an insecticide
10
Q
Which of the following alkyl halides has the smallest molecular dipole moment? A) CH3F B) CH3Cl C) CH2I2 D) CH2Cl2 E) CF4
A
E) CF4
11
Q
Among the following alkyl halides, choose the one with the lowest boiling point. A) t-butyl chloride B) n-butyl chloride C) t-butyl bromide D) n-butyl iodide E) t-butyl iodide
A
A) t-butyl chloride
12
Q
When 2,2-dimethylbutane is subjected to free-radical chlorination, \_\_\_\_\_\_\_\_ distinct monochlorinated products are possible and \_\_\_\_\_\_\_\_ of these contain asymmetric carbon atoms. A) 4, 2 B) 5, 0 C) 3, 0 D) 5, 2 E) 4, 0
A
A) 4, 2
13
Q
What type of intermediate is present in the SN2 reaction of cyanide with bromoethane? A) carbocation B) free radical C) carbene D) carbanion E) This reaction has no intermediate.
A
E) This reaction has no intermediate.
14
Q
Which of the following species is the least nucleophilic? A) H2O B) BF3 C) (CH3)3N D) CH3O- E) CN-
A
B) BF3
15
Q
Which of the following compounds is the most nucleophilic? A) CH3SH B) CH3OH C) H2O D) CH3CO2H E) BF3
A
A) CH3SH
16
Q
Which of the following factors is favorable for nucleophilicity but not basicity? A) highly polarizable B) low electronegativity C) negatively charged D) sterically hindered
A
A) highly polarizable
17
Q
Which of the following solvents could be described as polar and protic? A) ethanol B) acetonitrile C) dimethylformamide D) acetone E) 18-crown-6
A
A) ethanol
18
Q
Which of the following compounds will undergo an SN2 reaction most readily? A) (CH3)3CCH2I B) (CH3)3CCl C) (CH3)2CHI D) (CH3)2CHCH2CH2CH2I E) (CH3)2CHCH2CH2CH2Cl
A
D) (CH3)2CHCH2CH2CH2I
19
Q
Which of the following alkyl chlorides will undergo SN2 reaction most readily? A) 1-chloro-4-methylpentane B) 2-chloro-4-methylpentane C) 2-chloro-3-methylpentane D) 3-chloro-2-methylpentane E) 2-chloro-2-methylpentane
A
A) 1-chloro-4-methylpentane
20
Q
Which of the following statements describe a favorable attribute of a leaving group?
(More than one answer is possible.)
A) The leaving group should be highly polarizable.
B) The lower the electronegativity of the leaving group the better.
C) Good leaving groups need to have low steric hindrance.
D) The departed leaving group should have low basicity.
A
A and D
21
Q
Which of the following alkyl halides reacts most rapidly via an SN2 reaction with NaCN? A) 1-iodohexane B) 1-fluorohexane C) (R)-2-bromohexane D) iodocyclohexane E) 1-iodo-1-methylcyclohexane
A
A) 1-iodohexane
22
Q
Which of the compounds below undergoes solvolysis in aqueous ethanol most rapidly? A) cyclohexyl bromide B) methyl iodide C) isopropyl chloride D) 3-chloropentane E) 3-iodo-3-methylpentane
A
E) 3-iodo-3-methylpentane
23
Q
Which of the following alkyl bromides undergoes solvolysis in aqueous methanol most rapidly? A) PhCHBrCH3 B) (CH3)2CHCH2CH2Br C) (CH3)2CHCH2CHBrCH3 D) CH3CH2CH2CH2Br E) PhBr
A
A) PhCHBrCH3
24
Q
Which of the following alkyl halides reacts most rapidly via an SN1 solvolysis reaction in hot methanol? A) 1-iodohexane B) 1-fluorohexane C) (R)-2-bromohexane D) iodocyclohexane E) 1-iodo-1-methylcyclohexane
A
E) 1-iodo-1-methylcyclohexane
25
```
When ionization occurs at the single stereocenter of a chiral compound, the resulting carbocation is:
A) achiral.
B) chiral.
C) racemic.
D) optically active.
E) none of the above
```
A) achiral.
26
```
When trans-1-iodo-4-methylcyclohexane is heated in methanol, the product mixture is primarily ________.
A) a single, chiral compound
B) a mixture of diasteromeric ethers
C) a mixture of diasteromeric alcohols
D) a single, chiral alcohol
E) a single, chiral ether
```
B) a mixture of diasteromeric ethers
27
SN1 reactions usually proceed with:
A) equal amounts of inversion and retention at the center undergoing substitution.
B) slightly more inversion than retention at the center undergoing substitution.
C) slightly more retention then inversion at the center undergoing substitution.
D) complete inversion at the center undergoing substitution.
E) complete retention at the center undergoing substitution.
B) slightly more inversion than retention at the center undergoing substitution.
28
```
Which of the following alkyl halides is most likely to undergo rearrangement in an SN1 reaction?
A) 3-bromopentane
B) 2-chloro-3,3-dimethylpentane
C) 3-chloropentane
D) bromocyclohexane
E) 1-bromo-4-methylcyclohexane
```
B) 2-chloro-3,3-dimethylpentane
29
```
Which of the following alkyl chlorides is least likely to undergo rearrangement during a solvolysis reaction?
A) 2-chloro-4-methylpentane
B) 2-chloro-3-methylpentane
C) 2-chloro-2-methylpentane
D) cis-1-chloro-2-ethylcyclohexane
E) trans-1-chloro-2-ethylcyclohexane
```
C) 2-chloro-2-methylpentane
30
Which of the following statements correctly describe(s) E1 reactions of alkyl halides (RX)?
```
I. Rate = k[base]
II. Rate = k[base][RX]
III. Rate = k[RX]
IV. The reactions occur in two or more distinct steps.
V. Rearrangements are sometimes seen.
A) II and IV
B) III and V
C) I, IV, and V
D) I only
E) III, IV, and V
```
E) III, IV, and V
31
Dehydration of 1-butanol with concentrated sulfuric acid at 140∘C results in the formation of mainly trans-2-butene. According to these results, which of the following conclusions might be valid?
A) The reaction undergoes an E2-type elimination mechanism.
B) The reaction follows a new mechanism involving the formation of a carbanion intermediate.
Dehydration of 1-butanol with concentrated sulfuric acid at 140∘C results in the formation of mainly trans-2-butene. According to these results, which of the following conclusions might be valid?
A) The reaction undergoes an E2-type elimination mechanism.
B) The reaction follows a new mechanism involving the formation of a carbanion intermediate.
C) The reaction undergoes an E1-type elimination mechanism in conjunction with a hydride shift.
D) The reaction undergoes an E2-type elimination mechanism in conjunction with a methyl shift.
E) The reaction undergoes an E1-type elimination mechanism with no shifting.
D) The reaction undergoes an E2-type elimination mechanism in conjunction with a methyl shift.
E) The reaction undergoes an E1-type elimination mechanism with no shifting.
C) The reaction undergoes an E1-type elimination mechanism in conjunction with a hydride shift.
32
```
Which of the following alkyl halides can produce only a single alkene product from when treated with sodium methoxide?
A) 2-chloro-2-methylpentane
B) 3-chloro-3-ethylpentane
C) 3-chloro-2-methylpentane
D) 2-chloro-4-methylpentane
E) 2-chloro-3-ethylpentane
```
B) 3-chloro-3-ethylpentane
33
```
How many distinct alkene products results when 1-bromo-1-ethylcyclopentane is treated with NaOCH3?
A) 1
B) 2
C) 3
D) 4
```
B) 2
34
```
Which of the following mechanisms (SN1, SN2, E1, E2) feature(s) a carbocation intermediate?
A) SN1 only
B) SN2 only
C) E1 only
D) E2 only
E) both SN1 and E1
```
E) both SN1 and E1
35
```
In which of the following mechanisms (SN1, SN2, E1, E2) are alkenes the major reaction products?
A) SN1 only
B) SN2 only
C) E1 only
D) E2 only
E) both E1 and E2
```
E) both E1 and E2
36
```
Predict the two most likely mechanisms for the reaction of 2-iodohexane with sodium ethoxide.
A) SN2 and SN1
B) E1 and E2
C) SN2 and E2
D) E1 and SN1
E) E2 and SN1
```
C) SN2 and E2
37
```
Predict the two most likely mechanisms which occur when 2-iodohexane is heated in ethanol.
A) SN2 and SN1
B) E1 and E2
C) SN2 and E2
D) E1 and SN1
E) E2 and SN1
```
D) E1 and SN1
38
```
The major product from the reaction of 2-chloro-2-methylpentane with sodium ethoxide in ethanol results from which of the following mechanistic pathways?
A) SN1
B) SN2
C) E1
D) E2
E) E1cb
```
D) E2
39
```
The major product which results when 2-chloro-2-methylpentane is heated in ethanol is an ether. From which mechanistic pathway does this ether arise?
A) SN1
B) SN2
C) E1
D) E2
E) E1cb
```
A) SN1
40
```
When 3-iodo-3-ethylpentane is treated with sodium methoxide in methanol, the major organic product is an ________ that is generated through an ________ mechanism.
A) ether, SN1
B) ether, SN2
C) ether, E1
D) alkene, E2
E) alkene, E1
```
D) alkene, E2
41
```
When 3-iodo-3-ethylpentane is heated in methanol, the major organic product is an ________ that is generated through an ________ mechanism.
A) ether, SN1
B) ether, SN2
C) ether, E1
D) alkene, E2
E) alcohol, E1
```
A) ether, SN1
