AS Chemistry MCQ Help

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Har6547
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Hi,

I have pasted the MCQ below. How can the molecule 2-ethylbut-1-ene exist, because however I write it if has an ethyl functional group then it always has the longest C chain totaling 5. Maybe I am missing something/have done something incorrectly? Any help greatly appreciated. Thanks

What is the IUPAC name of the major product of the reaction between
2-ethylbut-1-ene and hydrogen bromide? [1 mark]

A 1-bromo-2-ethylbutane
B 2-bromo-2-ethylbutane
C 2-bromo-2-methylpentane
D 3-bromo-3-methylpentane
Last edited by Har6547; 4 months ago
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gingur
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You name alkenes with the longest chain that contains the double bond, so you are right that the longest chain for this molecule is 5 but as it has a C=C you want to name it in a way that shows it's an alkene, if that makes sense.

I got the answer as
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Har6547
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(Original post by gingur)
You name alkenes with the longest chain that contains the double bond, so you are right that the longest chain for this molecule is 5 but as it has a C=C you want to name it in a way that shows it's an alkene, if that makes sense.

I got the answer as
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Ohhhh... that makes sense, thanks a lot. and yes that's the correct answer
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