Skip to main content
Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides
Bruice - Organic Chemistry 8th Edition
Bruice8th EditionOrganic ChemistryISBN: 9780135213711당신이 사용하는 게 아니라요?교과서 변경
9장, 문제 86b

Which species in each pair is more stable?
b. Comparison of two carbocation structures to determine which is more stable.

검증된 단계별 안내
1
Step 1: Analyze the stability of carbocations based on their degree of substitution. Carbocations are classified as primary, secondary, or tertiary depending on the number of alkyl groups attached to the positively charged carbon. More substituted carbocations are generally more stable due to hyperconjugation and inductive effects.
Step 2: Compare the two species in the pair. The first species, CH3C+HCH2CH3, is a secondary carbocation because the positively charged carbon is attached to two alkyl groups (CH3 and CH2CH3). The second species, CH3CH2CH2C+H2, is a primary carbocation because the positively charged carbon is attached to only one alkyl group (CH2CH2CH3).
Step 3: Consider hyperconjugation. Secondary carbocations benefit from more hyperconjugation interactions compared to primary carbocations, as they have more adjacent C-H bonds that can donate electron density to stabilize the positive charge.
Step 4: Evaluate inductive effects. Alkyl groups are electron-donating through inductive effects, which help stabilize the positive charge on the carbocation. Secondary carbocations have more alkyl groups contributing to this stabilization compared to primary carbocations.
Step 5: Conclude that CH3C+HCH2CH3 (secondary carbocation) is more stable than CH3CH2CH2C+H2 (primary carbocation) due to the combined effects of hyperconjugation and inductive stabilization.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
6m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Carbocation Stability

Carbocations are positively charged carbon species that are classified based on their degree of substitution: primary, secondary, and tertiary. Tertiary carbocations are the most stable due to hyperconjugation and the inductive effect from surrounding alkyl groups, which help to disperse the positive charge. Understanding the stability of carbocations is crucial for predicting the reactivity and outcomes of organic reactions.
추천 영상:
05:58
Determining Carbocation Stability

Hyperconjugation

Hyperconjugation is a stabilizing interaction that occurs when the electrons in a sigma bond (C-H or C-C) interact with an adjacent empty p-orbital or a positively charged carbon. This effect allows for the delocalization of charge, which stabilizes carbocations. The more alkyl groups attached to the positively charged carbon, the greater the hyperconjugation, leading to increased stability.
추천 영상:
04:28
Understanding trends of alkene stability.

Inductive Effect

The inductive effect refers to the electron-donating or withdrawing effects of substituents through sigma bonds. Alkyl groups are electron-donating and can stabilize positive charges on carbocations by pushing electron density towards the positively charged carbon. This effect is significant in determining the relative stability of carbocations, as more electron-donating groups lead to greater stability.
추천 영상:
01:47
Understanding the Inductive Effect.