Which of the following chair conformations represents trans-1,4-dimethylcyclohexane?
A)I
B)II
C)III
D)IV

Question

Which of the following chair conformations represents trans-1,4-dimethylcyclohexane? 
A)I 
B)II 
C)III 
D)IV

Quizplus · Accepted Answer

In trans-1,4-dimethylcyclohexane, the two methyl groups (CH3) should be on opposite sides (trans) of the ring. This means that in the chair conformation, they should be oriented in axial and equatorial positions. In chair conformation I, the two axial methyl groups are diagonal from each other (diagonally trans), while the two equatorial methyl groups are also diagonal from each other (diaxial), so this is the correct conformation for trans-1,4-dimethylcyclohexane. Chair conformations II, III, and IV all have one pair of methyl groups in a cis configuration (on the same side) and one pair in a trans configuration (on opposite sides), so they are not correct for trans-1,4-dimethylcyclohexane.

Which of the Following Chair Conformations Represents Trans-1,4-Dimethylcyclohexane