Q: Which of the following is the correct rate law for an SN1 reaction?

$$\text{rate} = k[\text{substrate}]$$

Question 1

Which of the following statements best describes the difference between the SN1 and SN2 mechanisms?

Accepted Answer

SN1 reactions involve a carbocation intermediate and are unimolecular in the rate-determining step, while SN2 reactions are concerted and bimolecular in the rate-determining step.

Question 2

Given the following alkyl halides, which one will react fastest in an SN2 reaction?

Accepted Answer

$$\mathrm{CH_3CH_2CH_2Br}$$

Question 3

Which of the following is NOT considered a nucleophile?

Accepted Answer

$$\mathrm{CH_3CH_2^+}$$

Question 4

Which solvent would most likely increase the rate of an SN2 reaction?

Accepted Answer

Dimethyl sulfoxide (DMSO)

Question 5

Which of the following is the best leaving group for a substitution or elimination reaction?

Accepted Answer

$$\mathrm{I^-}$$

Question 6

A reaction of $$(S)-2-$$iodopentane with KCN in DMF proceeds via which mechanism and with what stereochemical outcome?

Accepted Answer

SN2, inversion of configuration

Question 7

Which of the following factors does NOT increase the rate of an E2 elimination reaction?

Accepted Answer

A weak base

Question 8

According to Zaitsev's rule, which alkene will be the major product in an E2 elimination?

Accepted Answer

The most substituted alkene

Question 9

Which of the following statements about the SN2 reaction mechanism is correct?

Accepted Answer

The reaction results in inversion of configuration at the stereocenter.

Question 10

Which of the following alkyl halides will NOT undergo an SN1 reaction?

Accepted Answer

Methyl halide

Question 11

A tertiary alkyl halide reacts with methanol under heat. Which mechanism and product are most likely?

Accepted Answer

E1, most substituted alkene

Question 12

Which of the following best explains why resonance decreases nucleophilicity?

Accepted Answer

Resonance delocalizes electron density, making the nucleophile less available for reaction.

Question 13

Which of the following conditions will favor an E2 elimination over an SN2 substitution for a secondary alkyl halide?

Accepted Answer

Use of a strong, bulky base and high temperature

Question 14

Which of the following is the correct rate law for an SN1 reaction?

Accepted Answer

$$	ext{rate} = k[	ext{substrate}]$$

Question 15

Which of the following nucleophiles is the strongest for an SN2 reaction in a polar aprotic solvent?

Accepted Answer

$$\mathrm{CH_3O^-}$$

Question 16

Which of the following best describes the stereochemical outcome of an SN1 reaction at a chiral center?

Accepted Answer

A racemic mixture of enantiomers

Question 17

Which of the following statements about E1 and E2 mechanisms is correct?

Accepted Answer

E2 reactions are concerted, while E1 reactions proceed via a carbocation intermediate.

Question 18

Which of the following will increase the likelihood of elimination over substitution in a reaction with a secondary alkyl halide?

Accepted Answer

Using a bulky base at high temperature

Question 19

Which of the following best describes the Hammond postulate as it applies to SN1 reactions?

Accepted Answer

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

Sustitución y Eliminación en Halogenuros de Alquilo: SN1, SN2, E1 y E2

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