Elimination Vs Substitution
Hardchemistry
Strong bulky base (t-BuOK) acting on 2-bromobutane favors formation of:
Select the correct option:
Solution
Incorrect! Answer:
Hofmann alkene (less substituted) major
- Base Nature: Potassium tert-butoxide (t−BuOK) is a very strong but bulky (sterically hindered) base.
- Approach: Due to its size, it cannot easily reach the more 'internal' β-hydrogen to give the more substituted alkene (Zaitsev product).
- Hydrogen abstraction: It prefers to abstract the most accessible (less hindered) β-hydrogen from the terminal methyl group.
- Result: This lead to the formation of But-1-ene (the Hofmann product) as the major product rather than But-2-ene.
- Note: Standard bases like EtO− or OH− would favor the Zaitsev product (But-2-ene).
🔒 Solution Hidden from View
Submit your answer to unlock the detailed step-by-step solution.
More elimination vs substitution Practice Questions
About This Question
- Subject
- chemistry
- Chapter
- halogen organics
- Topic
- elimination vs substitution
- Difficulty
- Hard
- Year
- 2025
Solution
Correct Answer:
Hofmann alkene (less substituted) major
- Base Nature: Potassium tert-butoxide (t−BuOK) is a very strong but bulky (sterically hindered) base.
- Approach: Due to its size, it cannot easily reach the more 'internal' β-hydrogen to give the more substituted alkene (Zaitsev product).
- Hydrogen abstraction: It prefers to abstract the most accessible (less hindered) β-hydrogen from the terminal methyl group.
- Result: This lead to the formation of But-1-ene (the Hofmann product) as the major product rather than But-2-ene.
- Note: Standard bases like EtO− or OH− would favor the Zaitsev product (But-2-ene).
This hard difficulty chemistry question is from the chapter halogen organics, covering the topic of elimination vs substitution. It appeared in the 2025 exam.
Looking for more practice? Explore all chemistry questions or browse halogen organics questions on RankGuru.