Which of the above structures represents the most stable conformation of 1-tert-butyl-3,5-dimethylcyclohexane?

1.a
2.b
3.c
4.d
5.e
Question 2What isomer of dichlorocyclohexane is represented by the Newman projection shown below?

1.1-axial; 3-axial
2.1-equatorial; 4-equatorial
3.1-equatorial; 3-equatorial
4.1-equatorial; 3-axial
5.1-equatorial; 4-axial
Question 3Which of the following statements is true concerning the isomers cis-1,2-dimethylcyclohexane and cis-1,3-dimethylcyclohexane?
1.They are not constitutional isomers.
2.They represent different conformations of the same molecule.
3.The favored conformer of the 1,3-isomer is more stable than that of the 1,2-isomer.
4.The favored conformer of the 1,3-isomer and that of the 1,2-isomer are equal in energy.
5.The relative stability of the two molecules cannot be determined.