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

enter image source here

2 Answers
Dec 30, 2016

Answer:

The correct answer is B.

Explanation:

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:

#"H"_3"C"-"CH"_2-"CH"_2-"CH"_2-"CH"_2-"CH"_3#

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.)