question_answer

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

Correct Answer: D

Solution :

[a] \[\underset{2,2-dimethyl\text{ }butane}{\mathop{C{{H}_{3}}C{{H}_{2}}-\overset{\begin{smallmatrix}  C{{H}_{3}} \\  | \end{smallmatrix}}{\mathop{\underset{\begin{smallmatrix}  | \\  C{{H}_{3}} \end{smallmatrix}}{\mathop{C}}\,}}\,-C{{H}_{3}}}}\,\] [b] \[\underset{2-methylpentane}{\mathop{C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}-\overset{\begin{smallmatrix}  C{{H}_{3}} \\  | \end{smallmatrix}}{\mathop{C}}\,H-C{{H}_{3}}}}\,\] [c] \[\underset{3-methylpentane}{\mathop{C{{H}_{3}}C{{H}_{2}}-\overset{\begin{smallmatrix}  C{{H}_{3}} \\  | \end{smallmatrix}}{\mathop{C}}\,H-C{{H}_{2}}C{{H}_{3}}}}\,\] [d]