Which of these is not an isomer of (the straight-chained) #"C"_6"H"_14# (hexane)?

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2 Answers
Dec 30, 2016

The correct answer is B.


All the molecules have the formula #"C"_6"H"_14#.

However, B is not an isomer of hexane.

That structure is hexane.

Dec 30, 2016

All isomers of one compound must have the same chemical formula. So, if it doesn't have 6 carbons and 14 hydrogens, it's out. Unfortunately, they all are valid under that condition.

The only differentiating factor then, is whether it is a different atomic connection with respect to:


which is the straight-chained structure.

#bb(B)# is the one that is the straight-chained structure (rotate the right end #90^@# counterclockwise), so it's not different from the original.

(It technically is an isomer, but it is not an isomer of itself. Not the best-worded question.)