Final answer:
Larger substituents on cyclohexane are most stable in equatorial positions due to reduced steric hindrance, particularly in the chair conformation which is the more stable puckered conformation of cyclohexane.
Step-by-step explanation:
Larger Substitutes on cyclohexane are most stable in equatorial positions. In cyclohexane, which prefers a chair conformation, there are position options for substituents: axial and equatorial. The larger the substituent, the more pronounced the steric repulsion is when the substituent is in the axial position due to 1,3-diaxial interactions with other hydrogens in the molecule. Thus, the chair conformation with the bulky group in an equatorial position will be more stable and favored at equilibrium.
This is especially relevant when considering the conformations of monosubstituted cyclohexanes. In such cases, the presence of a bulky group like a –CH3 group can lead to steric hindrance when it is placed at the axial position, compared to the equatorial position where such steric repulsions are minimized.
When analyzing substituted cyclohexanes, such as methylcyclopropane, propylcyclopentane, and ethylcycloheptane, it is crucial to predict the stability of the substituents based on their orientation in the chair conformation. For multiple substituents, their configuration and relative locations need to be considered to predict the stability correctly.