This question is about 2-methylbut-1-ene - AQA - A-Level Chemistry - Question 3 - 2022 - Paper 2
Question 3
This question is about 2-methylbut-1-ene.
1. Name the mechanism for the reaction of 2-methylbut-1-ene with concentrated sulfuric acid.
Outline the mechanism for thi... show full transcript
Worked Solution & Example Answer:This question is about 2-methylbut-1-ene - AQA - A-Level Chemistry - Question 3 - 2022 - Paper 2
Step 1
Name the mechanism for the reaction of 2-methylbut-1-ene with concentrated sulfuric acid.
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Answer
The mechanism involved in this reaction is called Electrophilic Addition. In this process, the concentrated sulfuric acid acts as an electrophile, attacking the double bond of 2-methylbut-1-ene.
Step 2
Outline the mechanism for this reaction to form the major product.
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Answer
The sulfuric acid donates a proton (H+) to the double bond, leading to the formation of a carbocation.
The carbocation rearranges to form a more stable secondary carbocation, if possible.
The bisulfate ion (HSO4-) then acts as a nucleophile, attacking the positively charged carbon atom of the carbocation.
This reaction results in the formation of the alkyl hydrogensulfate as the major product.
Step 3
Draw the structure of the minor product formed in the reaction in Question 03.1
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The minor product formed in the reaction is 2-methylbutyl hydrogen sulfate. Its structure can be represented as:
CH3
|
CH3-C-OSO3H
|
CH2
|
CH3
Step 4
Explain why this is the minor product.
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This is considered the minor product because it is formed from a less stable carbocation. The pathway leading to the major product involves the formation of a more stable carbocation due to rearrangement, making it more favorable than this alternative pathway.
Step 5
Draw the skeletal formula of a functional group isomer of 2-methylbut-1-ene.
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A functional group isomer of 2-methylbut-1-ene is 2-methylbutan-1-ol. It can be represented as:
CH3
|
CH3-C-CH2-CH2OH
|
CH3
Step 6
State the type of polymerisation.
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The type of polymerisation for 2-methylbut-1-ene is Addition Polymerisation.
Step 7
Draw the repeating unit for the polymer formed.
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The repeating unit for the polymer formed can be represented as:
