NUCLEOPHILIC SUBSTITUTION
(Quiz 6-3)

1. The reaction of tert-butyl bromide, (CH₃)₃CBr, with methanol in an inert solvent proceeds by an S_N1 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

2. Which of the following alkyl halides undergoes the fastest S_N2 reaction with sodium methylthiolate, NaSMe?

(A) methyl iodide

(B) ethyl iodide

(C) 2-bromopropane

(D) tert-butyl chloride

3. Which of the following alkyl halides undergoes the fastest solvolysis reaction with ethanol, CH₃CH₂OH?

(A) methyl fluoride

(B) ethyl bromide

(C) 2-chloropropane

(D) tert-butyl bromide

4. What is the major organic product obtained from the following reaction?

(A) 1

(B) 2

(C) 3

(D) 4

5. Which of the following anions is the most nucleophilic in polar protic solvents??

(A) F^-

(B) Cl^-

(C) Br^-

(D) I^-

6. Which of the following is the most nucleophilic?

(A) sodium ethoxide

(B) acetic acid

(C) methanol

(D) water

7. What is the major organic product obtained from the following reaction?

(A) 1

(B) 2

(C) 3

(D) 4

8. Which of the following represents the transition state of the S_N2 reaction between methyl iodide and ammonia?

(A) 1

(B) 2

(C) 3

(D) 4

9. Which of the following is not a characteristic of S_N1 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

10. Which of the following represents the transition state of the rate-determining step in the S_N1 reaction between tert-butyl chloride and water?

(A) 1

(B) 2

(C) 3

(D) 4