Question 1

Which of the following statements best explains why tertiary alkyl halides typically undergo $$E2$$ reactions when treated with strong bases?

Accepted Answer

Tertiary alkyl halides are too sterically hindered for $$S_N2$$ reactions, so strong bases favor $$E2$$ elimination.

Question 2

A primary alkyl halide reacts with a strong, non-bulky nucleophile. Which mechanism is most likely to occur?

Accepted Answer

$$S_N2$$

Question 3

Which of the following is a strong, non-nucleophilic base commonly used to promote $$E2$$ elimination reactions?

Accepted Answer

DBU

Question 4

When a secondary alkyl halide is treated with a strong, bulky base, which reaction pathway is favored?

Accepted Answer

$$E2$$ elimination

Question 5

Which of the following best describes the role of nucleophilicity in determining the reaction mechanism for alkyl halides?

Accepted Answer

Strong nucleophiles favor $$S_N2$$ substitution, while weak nucleophiles favor $$S_N1$$ substitution.

Question 6

Which of the following bases is considered both strong and non-nucleophilic, making it ideal for promoting $$E2$$ elimination without substitution?

Accepted Answer

DBN

Question 7

A secondary alcohol is treated with HBr. What is the major product and mechanism?

Accepted Answer

Alkyl bromide via $$S_N1$$ mechanism

Question 8

Why do strong acids like H$$_2SO$_4$$ promote elimination rather than substitution when reacting with alcohols?

Accepted Answer

They lack a good nucleophile, so elimination ($$E1) is $$favored.

Question 9

Which of the following is the correct structure for DBU?

Accepted Answer

$$1,8-$$Diazabicyclo$$[5.4.0]$$undec-7-ene

Question 10

Which of the following nucleophiles would most likely promote $$S_N2$$ substitution with a primary alkyl halide?

Accepted Answer

HO$$^-$$

Question 11

A tertiary alcohol is treated with HCl. What is the expected major product and mechanism?

Accepted Answer

Alkyl chloride via $$S_N1$$ mechanism

Question 12

Which of the following statements is true regarding the reactivity of secondary alkyl halides?

Accepted Answer

They can undergo both $$S_N2$$ and $$E2$$ reactions depending on the base/nucleophile.

Question 13

Which of the following is a weak nucleophile but a strong base, commonly used to promote elimination?

Accepted Answer

DBU

Question 14

What is the expected product when a methyl alcohol reacts with HBr?

Accepted Answer

Methyl bromide via $$S_N2$$ mechanism

Question 15

Which of the following is NOT a strong nucleophile?

Accepted Answer

CH$$_3$$COO$$^-$$

Question 16

A secondary alkyl halide is treated with a weak nucleophile. Which mechanism is most likely?

Accepted Answer

$$S_N1$$

Question 17

Which of the following best explains why tosic acid (TsOH) is non-nucleophilic?

Accepted Answer

Its conjugate base is highly stabilized by resonance, making it a poor nucleophile.

Question 18

Which of the following is a strong base but a weak nucleophile, often used to favor $$E2$$ elimination over substitution?

Accepted Answer

DBN

Question 19

Which of the following is the correct structure for DBN?

Accepted Answer

$$1,5-$$Diazabicyclo[4.3.0]non-5-ene

Alkyl Halides: Substitution and Elimination Mechanisms

Study Guide - Practice Questions