Question 1

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

Accepted Answer

$$NH_2$$^-$$

Question 2

Rank the following alkenes by stability, from most stable (1) to least stable (5): $$CH_2=$$CHCH_2CH_3$$, CH_2$=CH_2$, $$($$CH_3)_2C$$=$$CH_2$$, $$CH_3CH=$$CHCH_3$$, CH_2$=CHCH_2CH_2CH_3. $$Which is the most stable?

Accepted Answer

$$(CH_3$)_2C=CH_2$

Question 3

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

Accepted Answer

$$(CH_3$)_3CBr$$

Question 4

Upon photolysis with $$Br_2$$, which isomer of 1-bromo-2,2-dimethylpropane will react the fastest?

Accepted Answer

Isomer 3

Question 5

What is the major product when cyclohexyl chloride reacts with $$NaCN$$?

Accepted Answer

Cyclohexyl cyanide ($$C_6H_{11}CN)$$

Question 6

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

Accepted Answer

Dimethylformamide (DMF)

Question 7

If sodium methoxide ($$CH_3ONa) is $$replaced with sodium tert-butoxide ($$(CH_3$)_3CONa) in an $$elimination reaction, what happens to the ratio of $$S_N2 to E2 $$product?

Accepted Answer

The E2 product increases

Question 8

Assign the E/Z configuration to the following alkene: $$CH_3CH=CHCH_2CH_3. $$What is the correct configuration?

Accepted Answer

Z

Question 9

Which of the following statements best explains why tertiary alkyl halides react faster in $$S_N1$$ reactions than primary alkyl halides?

Accepted Answer

Tertiary carbocations are more stable due to hyperconjugation and inductive effects

Question 10

What is the expected major product when 1-bromo-2,2-dimethylpropane is treated with $$NaOEt ($$sodium ethoxide) in ethanol?

Accepted Answer

2,2-dimethylpropene

Question 11

Which of the following is a correct statement about the effect of a polar aprotic solvent on $$S_N2$$ reactions?

Accepted Answer

It increases the rate of $$S_N2$$ reactions by stabilizing the cation

Question 12

Which of the following compounds will yield the most stable carbocation upon $$S_N1$$ reaction?

Accepted Answer

2-bromo-2-methylpropane

Question 13

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

Accepted Answer

2-methylcyclohexene

Question 14

Which of the following is the best explanation for why $$S_N2$$ reactions are faster with primary alkyl halides than with tertiary alkyl halides?

Accepted Answer

Primary alkyl halides have less steric hindrance

Question 15

What is the major product when 2-bromopropane reacts with $$CH_3O^- in $$methanol?

Accepted Answer

Propene

Question 16

Which of the following statements is true regarding the use of sodium thiomethoxide ($$CH_3SNa) $$instead of sodium methoxide ($$CH_3ONa) in an$$ $$S_N2$$ reaction?

Accepted Answer

$$CH_3S^- is a $$better nucleophile than $$CH_3O^-$$

Question 17

Which of the following is the correct product when 1-bromopentane is treated with $$NaOEt in $$ethanol?

Accepted Answer

1-pentene (via E2 elimination)

Question 18

Which of the following reactions will produce a racemic mixture?

Accepted Answer

$$S_N1$$ reaction of 2-bromobutane with $$H_2O$$

Question 19

Which of the following is the best explanation for the increased rate of photolytic bromination at tertiary carbons?

Accepted Answer

Tertiary radicals are more stable due to hyperconjugation

Organic Chemistry II: Mechanisms, Reactivity, and Stereochemistry – Exam Study Guide

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