1. for Each of the Following Reaction Conditions, Determine If They Favor SN1, E1, SN2

1. For each of the following reaction conditions, determine if they favor SN1, E1, SN2, or E2. Include all that apply.

High Temperature E1 or E2

Low Temperature Sn1 or SN2

Tertiary substrates E1, SN1, or E2

Methyl or Primary substrates E2 or SN2

Strong base E1 or E2

High Concentration of strong base E2

Low base concentrations E1 or SN1

if base is strong E1

if base is weak SN1

Regioselective E1 or SN1

2o substrate with high concentration of base or nucleophile SN2 or E2

Requires L.G & beta hydrogen to be periplanar & preferably, anti-periplanar E2

2. If a reaction proceeds through an SN1 mechanism and the concentrations of both the substrate and nucleophile are doubled, the reaction rate will A) remain the same B) double C) triple D) quadruple

3. If a reaction proceeds through an SN2 mechanism and the concentrations of both the substrate and nucleophile are doubled, the reaction rate will A) remain the same B) double C) triple D) quadruple

4. For the following reaction carried out in aqueous ethanol, select the more reactive nucleophile in – each pair: CH3Br + Nu:  CH3-Nu + Br

Nucleophiles

First pair: I– and Cl– Second pair: HS– and OH-

A) I- & HS- B) Cl- & OH- C) I- & OH- D) Cl- & HS- 5. Which of the following is the best leaving group?

A) F- B) Cl- C) I- D) Br-

6. What is the mechanism of the following reaction?

A) SN1

B) SN2 C) E1 D) E2 E) both A and B

7. Which statement is true for SN2 reactions?

A) The rate of the reaction is dependent on the stability of a carbocation. B) The rate of reaction is dependent on just the substrate. C) The fastest reaction will occur with a tertiary halide. D) Displacement occurs with inversion of configuration. E) The mechanism is a two-step process.

8. Which bromide reacts fastest in SN2 reactions?

A) CH3Br

B) (CH3) 2CHBr

C) (CH3) 3CBr

D) (CH3) 3CCH2Br

E) CH3CH2Br

9. Which of the following is a polar aprotic solvent?

A) H2O

B) CH3CN

C) CH3OH

D) (CH3) 2S=O E) both B and D 10. Which statement(s) is/are true of an E1 elimination?

A) it is a two-step process and has the same first step as a SN1 mechanism B) it involves the formation of the carbocation from elimination of a good leaving group C) a common competing reaction is rearrangement of a less stable carbocation to a more stable carbocation D) the loss of a proton by the carbocation is a fast step E) all of the above

11. The slowest step of an SN1 reaction involves:

A) attack of the nucleophile on the substrate to form a pentavalent carbon. B) breaking the bond between the carbon and the leaving group to give a carbocation. C) combination of a nucleophile with the carbocation to give the product. D) loss of a proton from the nucleophile to give the product. E) none of the above.

12. Which of the following bromides will react faster with CH3OH in an SN1 reaction?

13. The SN2 mechanism for nucleophilic substitution reactions

A) involves two steps and occurs with inversion of configuration. B) involves one step and occurs with inversion of configuration. C) involves two steps and occurs with racemization. D) involves one step and occurs with retention of configuration. E) involves one step and occurs with racemization. 14. The energy-reaction diagram below is for

A) an SN2 reaction only.

B) an SN1 reaction only. C) an E2 reaction only. D) an E1 reaction only.

E) an SN1 or E1 reaction.

F) an SN2 or E2 reaction

15. How are basicity and leaving group ability related?

A) They are not related to each other B) Good leaving groups are strong bases C) Good leaving groups are weak bases

16. The transition state geometry in an SN2 reaction is?

A) Trigonal planar B) Tetrahedral C) Pentagonal D) Trigonal bipyramidal E) Octahedral

17. Which of the following compounds is least reactive in an SN2 reaction?

A B C D E

18. Which is the most stable isomer? A B C D E

19. Dehydration of alcohols is usually accomplished by?

A) Treating the alcohol with H2SO4 B) Treating the alcohol with HCl C) Treating the alcohol with NaOH

D) Treating the alcohol with Br2

E) Treating the alcohol with SOCl2

20. Zaitsev's rule states? A) Eliminations occur with the loss of an alpha hydrogen B) Eliminations occur with the loss of a beta hydrogen C) Eliminations occur with the loss of a beta hydrogen, and form the least substituted alkene. D) Eliminations occur with the loss of a beta hydrogen, and form the most substituted alkene. E) Eliminations occur with the loss of a beta hydrogen, and form cyclic alkenes.

After completing this, access the following site: http://www.chem.ox.ac.uk/vrchemistry/iom/default.html# And complete the practice & online quizzes regarding substitution & elimination reactions.