EK 1001 Orgo Q227

[Raiden2012]

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Can anyone please explain why C is the answer and not A? It seems they are both equally branched with the methyl group moving to adjacent carbon to form another branch.

Ok for those who don't have a book, I'll come up with an analogy. Which is more branched?
2,2 dimethylbutane or 2,3 dimethylbutane?

 

[Charles Darwin]

I'd say the latter is more branched. You still have somewhat of a straight chain, albeit 2 Cs, with the former.

 

[Raiden2012]

Yea, that was what I thought too. But the book answer states that 2,2 dimethyl is more branched. Just trying to confirm the answer because the book is not error free. Thanks

 

[shamwowzer]

Yea, that was what I thought too. But the book answer states that 2,2 dimethyl is more branched. Just trying to confirm the answer because the book is not error free. Thanks

I don't have the book, but it may have to do with how one can number and use each carbon as the primary chain. That would be my guess?

Sent from my DROID2 using Tapatalk

 

[sciencebooks]

Can anyone please explain why C is the answer and not A? It seems they are both equally branched with the methyl group moving to adjacent carbon to form another branch.

Ok for those who don't have a book, I'll come up with an analogy. Which is more branched?
2,2 dimethylbutane or 2,3 dimethylbutane?

I don't have the book and I think asking "more branched" is a poor choice of language on their part, but I chose 2,2 dimethylbutane so I'll try to explain why.

Basically, I was thinking of the effects of branching. One effect is a lower boiling point because of the fact that branching makes it more difficult for the separate molecules to stack on top of each other and have those interactions. While 2,3-dimethylbutance is symmetrical and would allow for some stacking (though not as easy or common as the straight chain), 2,2-dimethylbutane is NOT.

Hope that helps some, 🙂.

 

[Raiden2012]

Sciencebooks, that makes sense. Big thanks to you and others who contributed