Question

Which isomer of hexane has only two different sets of structurally equivalent hydrogen atoms?

• A. 2, 2 - dimethylbutane
• B. 2 - methylpentane
• C. 3 - methylpentane
• D. 2, 3 - dimethylbutane

Answer 1

The correct option is D 2, 3 - dimethylbutane

Hydrogens that have a different environment in terms of number of hydrogens on the same carbon atoms or adjacent $C-$ atoms are structurally equivalent.

So, $2,3-dimethylbutane$

$C{H}_3$ $C{H}_3$

$H_{3}C-\underset{|}{\stackrel{|}{C}}-\underset{|}{\stackrel{|}{C}}-C{H}_3$

$H$ $H$

There are $4-C{H}_3$ groups & these are all structurally equivalent because they are all attached to a carbon that has one hydrogen on it.

Option D is correct.