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When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition because
- a)H and Br are not trans
- b)there is no further B— H available
- c)vinyl bromide are very less reactive in E2 elimination reaction
- d)reactant is more stable than product
Correct answer is option 'C'. Can you explain this answer?
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Verified Answer
When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-buten...
Because vinyl bromide is less reactive and Alc. KoH is not that strong a base; we need a strong base like NaNH2 .
Most Upvoted Answer
When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-buten...
Explanation:
When 2,3-dibromobutane is treated with KOH in ethanol, it undergoes an elimination reaction known as E2 (bimolecular elimination) to form 2-bromo-2-butene. However, 2-bromo-2-butene does not undergo further dehydrobromination to form 2-butyne under similar conditions due to the following reasons:
1. Vinyl bromides are less reactive in E2 elimination:
Vinyl bromides, such as 2-bromo-2-butene, are less reactive in E2 elimination reactions compared to alkyl bromides. This is because the presence of a double bond in the molecule reduces the electron density on the carbon attached to the bromine atom, making it less nucleophilic. As a result, the rate of dehydrobromination is significantly lower for vinyl bromides.
2. Transition state stability:
In an E2 elimination reaction, the reaction proceeds through a transition state in which the leaving group (bromine) and the proton being removed are in the anti-coplanar conformation. In the case of 2-bromo-2-butene, the bromine and the proton are not in the anti-coplanar conformation, making the transition state less stable. This leads to a higher activation energy barrier for the elimination reaction, resulting in a slower rate of dehydrobromination.
3. Lack of availability of a β-hydrogen:
For an E2 elimination reaction to occur, there must be a β-hydrogen available on the carbon adjacent to the leaving group. In the case of 2-bromo-2-butene, there is no β-hydrogen present. The carbon attached to the bromine atom already has three substituents (two methyl groups and one hydrogen), leaving no β-hydrogen available for elimination.
Therefore, the correct answer is option 'C' - vinyl bromides are less reactive in E2 elimination reactions. The presence of a double bond reduces the electron density on the carbon attached to the bromine, making it less nucleophilic and less likely to undergo dehydrobromination. Additionally, the lack of a β-hydrogen and the less stable transition state further hinder the formation of 2-butyne.
When 2,3-dibromobutane is treated with KOH in ethanol, it undergoes an elimination reaction known as E2 (bimolecular elimination) to form 2-bromo-2-butene. However, 2-bromo-2-butene does not undergo further dehydrobromination to form 2-butyne under similar conditions due to the following reasons:
1. Vinyl bromides are less reactive in E2 elimination:
Vinyl bromides, such as 2-bromo-2-butene, are less reactive in E2 elimination reactions compared to alkyl bromides. This is because the presence of a double bond in the molecule reduces the electron density on the carbon attached to the bromine atom, making it less nucleophilic. As a result, the rate of dehydrobromination is significantly lower for vinyl bromides.
2. Transition state stability:
In an E2 elimination reaction, the reaction proceeds through a transition state in which the leaving group (bromine) and the proton being removed are in the anti-coplanar conformation. In the case of 2-bromo-2-butene, the bromine and the proton are not in the anti-coplanar conformation, making the transition state less stable. This leads to a higher activation energy barrier for the elimination reaction, resulting in a slower rate of dehydrobromination.
3. Lack of availability of a β-hydrogen:
For an E2 elimination reaction to occur, there must be a β-hydrogen available on the carbon adjacent to the leaving group. In the case of 2-bromo-2-butene, there is no β-hydrogen present. The carbon attached to the bromine atom already has three substituents (two methyl groups and one hydrogen), leaving no β-hydrogen available for elimination.
Therefore, the correct answer is option 'C' - vinyl bromides are less reactive in E2 elimination reactions. The presence of a double bond reduces the electron density on the carbon attached to the bromine, making it less nucleophilic and less likely to undergo dehydrobromination. Additionally, the lack of a β-hydrogen and the less stable transition state further hinder the formation of 2-butyne.
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When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer?
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When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer? for Class 11 2024 is part of Class 11 preparation. The Question and answers have been prepared according to the Class 11 exam syllabus. Information about When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Class 11 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer?.
When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer? for Class 11 2024 is part of Class 11 preparation. The Question and answers have been prepared according to the Class 11 exam syllabus. Information about When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Class 11 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer?.
Solutions for When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 11.
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When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer?, a detailed solution for When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer? has been provided alongside types of When 2,3-dibromobutane is treated with KOH in ethanol, 2-bromo-2-butene is formed which does not undergo further dehydrobromination to form 2-butyne under similar condition becausea)H and Br are not transb)there is no further B— H availablec)vinyl bromide are very less reactive in E2 elimination reactiond)reactant is more stable than productCorrect answer is option 'C'. Can you explain this answer? theory, EduRev gives you an
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