Q: Which of the following is the correct order of carbocation stability?

$$\text{tertiary} \u003e \text{secondary} \u003e \text{primary} \u003e \text{methyl}$$

Question 1

Which of the following best explains why tert-butyl chloride is the only product formed when HCl is added to 2-methylpropene?

Accepted Answer

The tert-butyl carbocation is more stable due to hyperconjugation from three alkyl groups.

Question 2

Which of the following is the correct order of carbocation stability?

Accepted Answer

$$	ext{tertiary} \u003e 	ext{secondary} \u003e 	ext{primary} \u003e 	ext{methyl}$$

Question 3

What is the major product when 3-methyl-1-butene reacts with HBr?

Accepted Answer

2-bromo-2-methylbutane

Question 4

Which mechanistic step explains the formation of the major product in the reaction of 3-methyl-1-butene with HBr?

Accepted Answer

A 1,2-hydride shift forms a more stable tertiary carbocation.

Question 5

Which statement best describes Markovnikov’s Rule as applied to the addition of HBr to an unsymmetrical alkene?

Accepted Answer

The Br atom attaches to the carbon with fewer hydrogens, forming the more stable carbocation intermediate.

Question 6

Which of the following best explains why alkyl groups stabilize carbocations?

Accepted Answer

They delocalize the positive charge by hyperconjugation.

Question 7

What is the major product when 3,3-dimethyl-1-butene reacts with HCl?

Accepted Answer

2-chloro-2,3-dimethylbutane

Question 8

Which rearrangement occurs during the reaction of 3,3-dimethyl-1-butene with HCl to give the major product?

Accepted Answer

A 1,2-methyl shift

Question 9

Which of the following best describes the role of $$\mathrm{H_2SO_4} in $$the acid-catalyzed hydration of alkenes?

Accepted Answer

It protonates water, making it a better electrophile.

Question 10

What is the product of the acid-catalyzed hydration of propene ($$\mathrm{CH_3CH=CH_2$}$$)?

Accepted Answer

$$\mathrm{CH_3CH(OH)CH_3$} (2-$$propanol)

Question 11

Which of the following statements about the catalytic hydrogenation of alkenes is correct?

Accepted Answer

Hydrogen atoms add to the same face of the double bond (syn addition).

Question 12

Which of the following is true regarding the formation of stereoisomers during the addition of HBr to 1-butene?

Accepted Answer

A chiral center is formed, resulting in a racemic mixture of enantiomers.

Question 13

Why do enzymes in biological systems typically produce only one stereoisomer as a product?

Accepted Answer

Enzymes are chiral and recognize only one stereoisomer as a substrate.

Question 14

Which product is formed in greater yield when 2-methyl-2-butene reacts with HI?

Accepted Answer

2-iodo-2-methylbutane

Question 15

Which of the following best describes the relationship between the two products formed by the acid-catalyzed addition of water to 3,4-dimethyl-3-heptene?

Accepted Answer

They are enantiomers.

Question 16

Which of the following is a real-world consequence of chirality in biological systems?

Accepted Answer

One enantiomer of a drug may be therapeutic, while the other is inactive or harmful.

Question 17

Which of the following best explains why the addition of HBr to 1-butene produces a racemic mixture?

Accepted Answer

The planar carbocation intermediate allows attack from either face, leading to both enantiomers.

Question 18

Which of the following is the correct mechanism for the acid-catalyzed hydration of an alkene?

Accepted Answer

Protonation of the alkene, nucleophilic attack by water, deprotonation to yield the alcohol.

Reactions of Alkenes: Mechanisms, Regioselectivity, and Stereochemistry

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