Q: Which of the following statements best describes the difference between SN1 and SN2 mechanisms in terms of their rate laws?

SN1 reactions have a rate law of $$\text{rate} = k[\text{substrate}]$$, while SN2 reactions have $$\text{rate} = k[\text{substrate}][\text{nucleophile}].$$

Q: Which of the following is the correct expression for the activation energy ($$E_a) in $$terms of the energy diagram of a reaction?

$$E_a = E_{\text{transition state}} - E_{\text{reactants}}$$

Question 1

Which of the following statements best describes the difference between SN1 and SN2 mechanisms in terms of their rate laws?

Accepted Answer

SN1 reactions have a rate law of $$	ext{rate} = k[	ext{substrate}]$$, while SN2 reactions have $$	ext{rate} = k[	ext{substrate}][	ext{nucleophile}].$$

Question 2

A reaction produces a major alkene product that is the most substituted. Which rule explains this outcome?

Accepted Answer

Zaitsev's Rule

Question 3

Which of the following solvents would best promote an SN2 reaction?

Accepted Answer

Acetone (aprotic solvent)

Question 4

Which of the following is the correct expression for the activation energy ($$E_a) in $$terms of the energy diagram of a reaction?

Accepted Answer

$$E_a = E_{	ext{transition state}} - E_{	ext{reactants}}$$

Question 5

Which of the following carbocations is the most stable?

Accepted Answer

Tertiary carbocation ($$R_3C^+)$$

Question 6

A reaction proceeds via a concerted mechanism, where bond breaking and bond forming occur simultaneously. Which type of reaction is this?

Accepted Answer

SN2

Question 7

Which of the following best describes a vicinal dihalide?

Accepted Answer

A compound with two halogens on adjacent carbon atoms

Question 8

Which of the following factors increases the rate of an E2 elimination reaction?

Accepted Answer

Using a strong base

Question 9

Which of the following is a characteristic of a racemic mixture?

Accepted Answer

It contains equal amounts of two enantiomers.

Question 10

Which product is favored in an E2 elimination when a bulky base such as tert-butoxide is used?

Accepted Answer

The Hoffmann product (least substituted alkene)

Question 11

Which of the following best explains the Hammond postulate?

Accepted Answer

The transition state resembles the species (reactants or products) to which it is closer in energy.

Question 12

Which of the following is true about the bond dissociation energy (BDE)?

Accepted Answer

BDE is the energy required to break a bond homolytically.

Question 13

Which of the following statements about alkyl halides is correct?

Accepted Answer

Tertiary alkyl halides favor SN1 mechanisms due to carbocation stability.

Question 14

Which of the following is the correct definition of a nucleophile?

Accepted Answer

A species that donates electrons to an electrophile.

Question 15

Which of the following is a consequence of steric hindrance in SN2 reactions?

Accepted Answer

It decreases the rate of reaction.

Question 16

Which of the following is true about the transition state in a chemical reaction?

Accepted Answer

It is the highest energy point along the reaction coordinate.

Question 17

Which of the following best describes a unimolecular reaction?

Accepted Answer

A reaction where the rate depends only on the concentration of one reactant.

Question 18

Which of the following is the correct formula for the enthalpy change ($$\Delta H) of a $$reaction?

Accepted Answer

$$\Delta H = E_{	ext{products}} - E_{	ext{reactants}}$$

Question 19

Which of the following statements is true regarding the formation of alkynes from elimination reactions?

Accepted Answer

Alkynes are formed by two consecutive elimination reactions from a vicinal dihalide.

Organic Chemistry: Key Vocabulary and Core Skills for Reaction Mechanisms (Chapters 6/7)

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