Quiz 11 Flashcards
- Which of the following reactions corresponds to a substitution?
A. propene ® 1,2-dibromopropane
B. 1-iodopropane ® propene
C. propene ® propane
D. 1-iodopropane ® 1-bromopropane
D. 1-iodopropane ® 1-bromopropane
- Which of the following reactions corresponds to a substitution?
A. tert-butanol ® tert-butyl chloride
B. tert-butanol ® 2-methylpropene
C. 3,3-dimethyl-2-butanol ® 2,3-dimethyl-2-butene
D. cyclohexene ® 1,2-dichlorocyclohexane
A. tert-butanol ® tert-butyl chloride
- Which of the following statements related to SN1 reactions is not true?
A. The heterolysis of a bond between atoms which do not bear formal charges always produces a cation and an anion
B. The charged carbon atom of a carbocation has a complete octet of valence shell electrons
C. Carbocations are Lewis acids
D. Nucleophiles seek centers of low electron density
B. The charged carbon atom of a carbocation has a complete octet of valence shell electrons
- Which of the following statements related to SN1 reactions is not true?
A. The SN1 reaction can be described as a heterolytic bond cleavage followed by nucleophilic attack
B. Carbocations are electrophilic
C. The charged carbon atom of a carbocation has an unfilled valence shell
D. Nucleophiles are Lewis acids
D. Nucleophiles are Lewis acids
- What is the equation for the rate of formation of tert-butyl alcohol from the reaction of tert-butyl bromide (t-BuBr) with water by an SN1 mechanism?
A. Rate = k [t-BuBr]
B. Rate = k [t-BuBr][H2O]
C. Rate = k [H2O]
D. Rate = k [t-BuBr]2
A. Rate = k [t-BuBr]
- What is the equation for the rate of formation of 1-iodobutane from the reaction of 1-chlorobutane (BuCl) with NaI by an SN2 mechanism?
A. Rate = k [BuCl]
B. Rate = k [BuCl][NaI]
C. Rate = k [NaI]
D. Rate = k [BuCl]2
B. Rate = k [BuCl][NaI]
- The reaction of methyl iodide with sodium azide, NaN3, proceeds by an SN2 mechanism. What is the effect of doubling the concentration of NaN3 on the rate of the reaction?
A. the rate remains the same
B. the rate decreases by a factor of 2
C. the rate increases by a factor of 2
D. the rate increases by a factor of 4
C. the rate increases by a factor of 2
- The reaction of 1-bromopropane with sodium iodide gives 1-iodopropane. What is the effect of doubling the concentration of NaI on the rate of the reaction?
A. the rate remains the same
B. the rate decreases by a factor of 2
C. the rate increases by a factor of 2
D. the rate increases by a factor of 4
C. the rate increases by a factor of 2
- The reaction of tert-butyl bromide, (CH3)3CBr, with methanol in an inert solvent proceeds by an SN1 mechanism to give tert-butyl methyl ether, (CH3)3COCH3. What is the effect of doubling the concentration of methanol on the rate of the reaction?
A. the rate remains the same
B. the rate decreases by a factor of 2
C. the rate increases by a factor of 2
D. the rate increases by a factor of 4
A. the rate remains the same
- The reaction of tert-butyl chloride, (CH3)3CCl, with water in an inert solvent gives tert-butyl alcohol, (CH3)3COH. What is the effect of doubling the concentration of water on the rate of the reaction?
A. the rate remains the same
B. the rate decreases by a factor of 2
C. the rate increases by a factor of 2
D. the rate increases by a factor of 4
A. the rate remains the same
- Which of the following alkyl halides undergoes the fastest SN2 reaction with sodium azide, NaN3?
A. 1-fluorohexane
B. 1-chlorohexane
C. 1-bromohexane
D. 1-iodohexane
D. 1-iodohexane
- Which of the following alkyl halides undergoes the fastest SN2 reaction with sodium cyanide, NaCN?
A. methyl iodide
B. ethyl iodide
C. 2-iodopropane
D. tert-butyl iodide
A. methyl iodide
- Which of the following alkyl halides undergoes the fastest SN2 reaction with sodium methylthiolate, NaSMe?
A. methyl iodide
B. ethyl iodide
C. 2-bromopropane
D. tert-butyl chloride
A. methyl iodide
- Which of the following alkyl halides undergoes the fastest solvolysis reaction with formic acid, HCOOH?
A. tert-butyl fluoride
B. tert-butyl chloride
C. tert-butyl bromide
D. tert-butyl iodide
D. tert-butyl iodide
- Which of the following alkyl halides undergoes the fastest solvolysis reaction with methanol, CH3OH?
A. methyl chloride
B. ethyl chloride
C. 2-chloropropane
D. tert-butyl chloride
D. tert-butyl chloride
- What is the major product formed upon treatment of (R) 1-bromo-4-methylhexane with sodium cyanide?
A. (R) 1-cyano-4-methylhexane
B. (S) 1-cyano-4-methylhexane
C. (R) 4-methyl-1-hexene
D. (S) 4-methyl-1-hexene
A. (R) 1-cyano-4-methylhexane
- What is the major product formed upon treatment of (R) 2-bromohexane with sodium cyanide?
A. (R) 2-cyanohexane
B. (S) 2-cyanohexane
C. 1-hexene
D. 2-hexene
A. (R) 2-cyanohexane
- What is(are) the major organic product(s) obtained from the following substitution reaction?
D. 1, 2 and 3
- What is(are) the major organic product(s) obtained from the following substitution reaction?
D. 1, 2 and 3
- In which of the following solvents would the reaction of 1-bromobutane with sodium azide, NaN3, proceed the fastest?
A. acetic acid
B. ethanol
C. water
D. acetonitrile
D. acetonitrile
- Which of the following anions is the most nucleophilic in polar protic solvents?
A. F-
B. Cl-
C. Br-
D. I-
D. I-
- Which of the following anions is the most nucleophilic in polar aprotic solvents?
A. F-
B. Cl-
C. Br-
D. I-
A. F-
- Which of the following compounds is the most nucleophilic in polar protic solvents?
A. H2O
B. NH3
C. H2S
D. PH3
D. PH3
- Which of the following is the most nucleophilic?
A. sodium ethoxide
B. acetic acid
C. methanol
D. water
A. sodium ethoxide
- Which of the following anions is the best leaving group in an SN1 reaction?
A. F-
B. HO-
C. NH2-
D. Cl-
D. Cl-
- Which of the following is the best leaving group in an SN2 reaction?
A. F-
B. H3C-
C. CH3O2SO-
D. HO-
C. CH3O2SO-
- Which of the following statements is not true regarding the SN2 reaction of (R)-2-bromobutane with sodium cyanide?
A. the reaction proceeds with inversion of configuration
B. the rate is proportional to the concentration of sodium cyanide
C. the rate is proportional to the concentration of (R)-2-bromobutane
D. the rate of the reaction is independent of the identity of the solvent
D. the rate of the reaction is independent of the identity of the solvent
- Which of the following statements is true regarding the reaction of tert-butyl bromide with water?
A. the rate is proportional to the concentration of tert-butyl bromide
B. the rate is proportional to the concentration of water
C. the rate is independent of the identity of the solvent
D. the rate of the reaction is independent of the temperature
A. the rate is proportional to the concentration of tert-butyl bromide
- Which of the following is not a characteristic of SN2 reactions?
A. the electrophilic carbon undergoes inversion of stereochemistry
B. the rate is proportional to the concentration of substrate
C. the rate is proportional to the concentration of nucleophile
D. the rate is independent of the solvent
D. the rate is independent of the solvent
- Which of the following is not a characteristic of SN1 reactions?
A. the electrophilic carbon undergoes inversion of stereochemistry
B. the rate is proportional to the concentration of substrate
C. the reaction proceeds faster in a more polar solvent
D. the rate is independent of the concentration of nucleophile
A. the electrophilic carbon undergoes inversion of stereochemistry
- Which of the following statements is not true regarding SN2 reactions?
A. A carbocation intermediate is formed.
B. The mechanism has only one step.
C. Aprotic solvents are good choices for SN1 reactions.
D. The stereochemical outcome is inversion at the carbon bearing the leaving group.
A. A carbocation intermediate is formed.
- Which of the following statements is not true regarding SN1 reactions?
A. A carbocation intermediate is formed.
B. The mechanism has only one step.
C. Polar, protic solvents are good choices for SN1 reactions.
D. The stereochemical outcome is racemization at the carbon bearing the leaving group.
B. The mechanism has only one step.
- Which of the following energy diagrams represents the course of an exothermic SN1 reaction?
A. 1
- Which of the following energy diagrams represents the course of an exothermic SN2 reaction?
C. 3
1) What is the nucleophile in the reaction shown below?
B) II
2) Which of the following is not a nucleophile?
C) +CH3
3) Which of the following best describes the carbon-chlorine bond of an alkyl chloride?
A) nonpolar; no dipole
B) polar; δ+ at carbon and δ- at chlorine
C) polar; δ- at carbon and δ+ at chlorine
D) ionic
E) none of the above
B) polar; δ+ at carbon and δ- at chlorine
4) Which of the following is not normally considered to be a nucleophile?
D) CH3CH2+
7) Identify the alkyl halide that reacts the fastest in a SN2 reaction.
A) 2-chloro-2-methylpropane
B) 2-chlorobutane
C) 1-chlorobutane
D) chloromethane
D) chloromethane
8) Identify the alkyl halide that reacts the fastest in an SN2 reaction.
A) 1-chloropropane
B) 1-bromopropane
C) 1-fluoropropane
D) 1-iodopropane
D) 1-iodopropane
9) Identify the strongest nucleophile in an SN2 reaction.
A) isopropoxide ion
B) tert-butoxide ion
C) ethoxide ion
D) tert-pentoxide ion
C) ethoxide ion
10) Which of the following are the substitution products of the reaction shown below?
CH3CH2Br + -OH → ?
A) CH3CH2BrH+ + O-
B) HOCH2CH2Br
C) CH3CH2OH + Br-
D) CH2CH2 + Br- + H2O
E) CH2CHBr + H2O
C) CH3CH2OH + Br-
11) Which of the following alkyl halides gives the slowest SN2 reaction?
12) Assuming no other changes, what is the effect of doubling only the concentration of the alkyl halide in the above SN2 reaction?
B) doubles the rate
13) Assuming no other changes, what is the effect of doubling both the alkyl halide and the nucleophile concentrations in the above reaction?
A) no change
B) doubles the rate
C) triples the rate
D) quadruples the rate
E) rate is halved
D) quadruples the rate
14) Which of the following SN2 reactions is the fastest?
B) CH3CH2CH2I + HO- → CH3CH2CH2OH + I-