Question 1

Which will be true for any actual or potential nucleophilic substitution reaction?

Accepted Answer

A) "$\Delta$HS1U1P1$\circ$S1S1P0 is positive." 
B) "$\Delta$HS1U1P1$\circ$S1S1P0 is negative." 
C) "$\Delta$G‡ is positive." 
D) "$\Delta$GS1U1P1$\circ$S1S1P0 is positive." 
E) "$\Delta$GS1U1P1$\circ$S1S1P0 is negative." 
A) "$\Delta$HS1U1P1$\circ$S1S1P0 is positive." 
B) "$\Delta$HS1U1P1$\circ$S1S1P0 is negative." 
C) "$\Delta$G‡ is positive." 
D) "$\Delta$GS1U1P1$\circ$S1S1P0 is positive." 
E) "$\Delta$GS1U1P1$\circ$S1S1P0 is negative."

Question 2

Which nucleophilic substitution reaction is not likely to occur?

Accepted Answer

A) I-+ CH3CH2-Cl $\to$ CH3CH2-I + Cl- 
B) I- + CH3CH2-Br $\to$ CH3CH2-I + Br- 
C) I- + CH3CH2-OH $\to$CH3CH2-I + OH- 
D) CH3O-+ CH3CH2-Br $\to$ CH3CH2-OCH3 + Br- 
E) OH-+ CH3CH2-Cl $\to$ CH3CH2-OH + Cl- 
A) I-+ CH3CH2-Cl $\to$ CH3CH2-I + Cl- 
B) I- + CH3CH2-Br $\to$ CH3CH2-I + Br- 
C) I- + CH3CH2-OH $\to$CH3CH2-I + OH- 
D) CH3O-+ CH3CH2-Br $\to$ CH3CH2-OCH3 + Br- 
E) OH-+ CH3CH2-Cl $\to$ CH3CH2-OH + Cl-

Question 3

A student has isolated a chiral alkyl halide (shown below)with a specific rotation of [$\alpha$] = +22.1o.The student decided to store the compound in the solvent MeOH overnight.However,reanalysis of the alkyl halide showed a new chemical formula of C11H16O with a specific rotation of [$\alpha$] = 0o.Suggest a mechanism to justify these results.

Accepted Answer

In leaving the compound in MeOH a solvol

Question 4

The substitution mechanism whose rate depends primarily on the degree of steric hindrance around the leaving group is the ___.

Accepted Answer

The answer of The substitution mechanism whose rate depends primarily...

Question 5

The p orbital of the charged carbon in the isopropyl cation,(CH3)2CH+,contains how many electrons?

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
E) 4 
A) 0 
B) 1 
C) 2 
D) 3 
E) 4

Question 6

Which of the following statements is (are)true of SN1 reactions of alkyl halides in general?

Accepted Answer

A) The rate of an SN1 reaction depends on the concentration of the alkyl halide. 
B) The rate of an SN1 reaction depends on the concentration of the nucleophile. 
C) SN1 reactions of alkyl halides are favored by polar solvents. 
D) The rate of an SN1 reaction depends on the concentration of the alkyl halide and SN1 reactions of alkyl halides are favored by polar solvents. 
E) The rate of an SN1 reaction depends on the concentration of the alkyl halide and the concentration of the nucleophile,and SN1 reactions of alkyl halides are favored by polar solvents. 
A) The rate of an SN1 reaction depends on the concentration of the alkyl halide. 
B) The rate of an SN1 reaction depends on the concentration of the nucleophile. 
C) SN1 reactions of alkyl halides are favored by polar solvents. 
D) The rate of an SN1 reaction depends on the concentration of the alkyl halide and SN1 reactions of alkyl halides are favored by polar solvents. 
E) The rate of an SN1 reaction depends on the concentration of the alkyl halide and the concentration of the nucleophile,and SN1 reactions of alkyl halides are favored by polar solvents.

Question 7

Consider the SN2 reaction of butyl bromide with OH- ion. CH3CH2CH2CH2Br + OH- $\to$ CH3CH2CH2CH2OH + Br-
Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both butyl bromide and OH- ion?

Accepted Answer

A) No effect. 
B) It would double the rate. 
C) It would triple the rate. 
D) It would increase the rate four times. 
E) It would increase the rate six times. 
A) No effect. 
B) It would double the rate. 
C) It would triple the rate. 
D) It would increase the rate four times. 
E) It would increase the rate six times.

Question 8

Identify the leaving group in the following reaction.

Accepted Answer

A) C6H5S- 
B) Na+ 
C) CH3CH2I 
D) C6H5SCH2CH3 
E) I- 
A) C6H5S- 
B) Na+ 
C) CH3CH2I 
D) C6H5SCH2CH3 
E) I-

Question 9

Which of the following is not a nucleophile?

Accepted Answer

A) H2O 
B) CH3O- 
C) NH3 
D) NH4+ 
E) All are nucleophiles. 
A) H2O 
B) CH3O- 
C) NH3 
D) NH4+ 
E) All are nucleophiles.

Question 10

Which is the most reactive nucleophile in DMF (structure shown below)?

Accepted Answer

A) F- 
B) Cl- 
C) Br- 
D) I- 
E) All of these choices are equally reactive. 
A) F- 
B) Cl- 
C) Br- 
D) I- 
E) All of these choices are equally reactive.

Question 11

Which alkyl halide would you expect to undergo an SN2 reaction most slowly?

Accepted Answer

A) 1-bromohexane 
B) 1-bromo-2-methylpentane 
C) 1-bromo-3-methylpentane 
D) 1-bromo-4-methylpentane 
E) 1-bromo-2,2-dimethylbutane 
A) 1-bromohexane 
B) 1-bromo-2-methylpentane 
C) 1-bromo-3-methylpentane 
D) 1-bromo-4-methylpentane 
E) 1-bromo-2,2-dimethylbutane

Question 12

An increase in the temperature at which a reaction is carried out increases

Accepted Answer

A) the collision frequency. 
B) the fraction of molecules with proper orientation. 
C) the fraction of molecules with energy greater than Eact. 
D) More than one of these choices. 
E) None of these choices. 
A) the collision frequency. 
B) the fraction of molecules with proper orientation. 
C) the fraction of molecules with energy greater than Eact. 
D) More than one of these choices. 
E) None of these choices.

Question 13

Consider the SN2 reaction of 1-chloro-5-methylhexane with CN- ion.   
Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and NaCN?

Accepted Answer

A) No effect. 
B) It would double the rate. 
C) It would triple the rate. 
D) It would increase the rate four times. 
E) It would increase the rate six times. 
A) No effect. 
B) It would double the rate. 
C) It would triple the rate. 
D) It would increase the rate four times. 
E) It would increase the rate six times.

Question 14

Select the potential energy diagram that represents an exothermic (exergonic)reaction.

Accepted Answer

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

Question 15

Which of the following nucleophiles will react the fastest with 1-bromoptopane in ethanol?

Accepted Answer

A) SH- 
B) OH- 
C) H2O 
D) H2S 
E) All react at about the same rate. 
A) SH- 
B) OH- 
C) H2O 
D) H2S 
E) All react at about the same rate.

Question 16

Which alkyl halide would be most reactive in an SN1 reaction?

Accepted Answer

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

Question 17

Ambident nucleophiles are ones which can react with a substrate at either of two nucleophilic sites.Which of the following is not an ambident nucleophile?

Accepted Answer

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

Question 18

The substitution mechanism whose rate depends primarily on the relative stability of the intermediate carbocation is the ___.

Accepted Answer

The answer of The substitution mechanism whose rate depends primarily...

Question 19

Which of the following is the poorest leaving group?

Accepted Answer

A) H- 
B) CH3O- 
C) H2O 
D) OH- 
E) NH2- 
A) H- 
B) CH3O- 
C) H2O 
D) OH- 
E) NH2-

Question 20

Identify the nucleophile in the following reaction: 2 H2O + RX $\to$ ROH + H3O+ + X-

Accepted Answer

A) X- 
B) H3O+ 
C) ROH 
D) H2O 
E) RX 
A) X- 
B) H3O+ 
C) ROH 
D) H2O 
E) RX

Exam 6: Nucleophilic Reactions

Which will be true for any actual or potential nucleophilic substitution reaction?

Which nucleophilic substitution reaction is not likely to occur?

The substitution mechanism whose rate depends primarily on the degree of steric hindrance around the leaving group is the ___.

The p orbital of the charged carbon in the isopropyl cation,(CH3)2CH+,contains how many electrons?

Which of the following statements is (are)true of SN1 reactions of alkyl halides in general?

Consider the SN2 reaction of butyl bromide with OH- ion. CH3CH2CH2CH2Br + OH- →\to→ CH3CH2CH2CH2OH + Br- Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both butyl bromide and OH- ion?

Identify the leaving group in the following reaction.

Which of the following is not a nucleophile?

Which is the most reactive nucleophile in DMF (structure shown below)?

Which alkyl halide would you expect to undergo an SN2 reaction most slowly?

An increase in the temperature at which a reaction is carried out increases

Consider the SN2 reaction of 1-chloro-5-methylhexane with CN- ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and NaCN?

Select the potential energy diagram that represents an exothermic (exergonic)reaction.

Which of the following nucleophiles will react the fastest with 1-bromoptopane in ethanol?

Which alkyl halide would be most reactive in an SN1 reaction?

Ambident nucleophiles are ones which can react with a substrate at either of two nucleophilic sites.Which of the following is not an ambident nucleophile?

The substitution mechanism whose rate depends primarily on the relative stability of the intermediate carbocation is the ___.

Which of the following is the poorest leaving group?

Identify the nucleophile in the following reaction: 2 H2O + RX →\to→ ROH + H3O+ + X-

The Basics

Families of Carbon

Acids and Bases

Nomenclature and Conformations of Alkanes and Cycloalkanes

Stereochemistry

Alkenes and Alkynes I

Alkenes and Alkynes II

Nuclear Magnetic Resonance and Mass Spectrometry

Radical Reactions

Alcohols and Ethers

Alcohols From Carbonyl Compounds

Conjugated Unsaturated Systems

Aromatic Compounds

Reactions of Aromatic Compounds

Aldehydes and Ketones

Carboxylic Acids and Their Derivatives

Reactions at the Α Carbon of Carbonyl Compounds

Condensation and Conjugate Addition Reactions of Carbonyl Compounds

Amines

Transition Metal Complexes

Carbohydrates

Lipids

Amino Acids and Proteins

Nucleic Acids and Protein Synthesis

Filters

The p orbital of the charged carbon in the isopropyl cation,(CH₃)₂CH⁺,contains how many electrons?

Which of the following statements is (are)true of S_N1 reactions of alkyl halides in general?

Consider the S_N2 reaction of butyl bromide with OH^- ion. CH₃CH₂CH₂CH₂Br + OH^- $\to$ CH₃CH₂CH₂CH₂OH + Br^- Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both butyl bromide and OH- ion?

Which alkyl halide would you expect to undergo an S_N2 reaction most slowly?

Consider the S_N2 reaction of 1-chloro-5-methylhexane with CN- ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and NaCN?

Which alkyl halide would be most reactive in an S_N1 reaction?

Identify the nucleophile in the following reaction: 2 H₂O + RX $\to$ ROH + H₃O⁺ + X^-