Question 1

Which of the following nucleophiles will react the fastest in an $$S_N2$$ reaction with iodomethane ($$CH_3I$$)?

Accepted Answer

Methoxide ion ($$CH_3O^-)$$

Question 2

Rank the following alkenes by stability (most stable to least stable): 1) 2,3-dimethyl-2-butene, 2) trans-2-butene, 3) cis-2-butene, 4) 1-butene, 5) isobutene. Which is the most stable?

Accepted Answer

2,3-dimethyl-2-butene

Question 3

Which compound will react the fastest in an $$S_N1$$ reaction?

Accepted Answer

tert-butyl bromide

Question 4

Upon photolysis with $$Br_2$$, which isomer of 1,2-dimethylcyclohexane will react the slowest?

Accepted Answer

(1S,2S)-1-bromo-1,2-dimethylcyclohexane

Question 5

Which solvent would increase the rate of an $$S_N2$$ reaction the most?

Accepted Answer

Dimethyl sulfoxide (DMSO)

Question 6

What would happen to the ratio of $$S_N2$$ product versus E2 product if sodium methoxide ($$CH_3ONa) $$was changed to sodium tert-butoxide ($$t-$$BuONa)?

Accepted Answer

The E2 product would increase due to greater steric hindrance.

Question 7

Which of the following statements best explains why $$S_N1$$ reactions are faster in polar protic solvents?

Accepted Answer

Polar protic solvents stabilize the carbocation intermediate.

Question 8

Assign the E/Z configuration to the following alkene: $$CH_3CH_2CH=CHCH_2CH_3$$

Accepted Answer

E

Question 9

Which of the following is the major product when 2-bromopropane reacts with sodium methoxide ($$CH_3ONa) in $$methanol?

Accepted Answer

Propene

Question 10

A student treats cyclohexanol with concentrated $$H_2SO_4. $$What is the major product?

Accepted Answer

Cyclohexene

Question 11

Which of the following statements is true regarding the $$S_N2$$ reaction mechanism?

Accepted Answer

The reaction rate depends on both the substrate and nucleophile concentrations.

Question 12

What is the expected product when 1-bromopentane is treated with sodium cyanide ($$NaCN$$)?

Accepted Answer

Pentanenitrile ($$CH_3CH_2CH_2CH_2CH_2CN)$$

Question 13

Which of the following would most likely undergo E2 elimination rather than $$S_N2$$ substitution when treated with a strong base?

Accepted Answer

2-bromo-2-methylpropane

Question 14

Which of the following is the major monobrominated product when 2-methylpropane is treated with $$Br_2$$ and light?

Accepted Answer

2-bromo-2-methylpropane

Question 15

Which of the following statements best explains why tertiary alkyl halides favor $$S_N1$$ and E1 mechanisms?

Accepted Answer

Tertiary alkyl halides form stable carbocations due to hyperconjugation and inductive effects.

Question 16

What is the effect of using sodium thiomethoxide ($$CH_3SNa) $$instead of sodium methoxide ($$CH_3ONa) in an$$ $$S_N2$$ reaction?

Accepted Answer

The $$S_N2$$ rate increases due to the softer nucleophile.

Question 17

Which of the following is the major product when 1-bromo-2-methylcyclohexane reacts with sodium ethoxide ($$NaOEt) in $$ethanol?

Accepted Answer

1,2-dimethylcyclohexene

Question 18

Which of the following is the correct product when 1-chlorocyclohexane reacts with sodium cyanide ($$NaCN$$)?

Accepted Answer

Cyclohexanenitrile

Question 19

Which of the following is the major product when 2-bromopentane is treated with sodium methanethiolate ($$CH_3SNa$$)?

Accepted Answer

2-methylthiopentane

Organic Chemistry Exam #2 Study Guide: Substitution, Elimination, and Alkene Reactions

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