Final answer:
A large group in an axial position on a cyclohexane ring will be higher in energy than in an equatorial position due to steric repulsion. Equatorial positions minimize this strain, making them more stable and common, especially in biologically relevant molecules like monosaccharides.
Step-by-step explanation:
In general, a large group in an axial position on a cyclohexane ring will be higher in energy than in an equatorial position. This is due to steric repulsion caused by 1,3-diaxial interactions, where the large group in the axial position experiences close contact with hydrogens on other axial positions of the same face of the cyclohexane ring. Chair conformations of cyclohexane with bulky groups at equatorial positions are more stable and thus more common in nature because they minimize this steric strain.
Throughout chemistry, particularly in the study of organic molecules like cyclohexane, this preference for equatorial over axial positioning is observed in many chemical structures, such as monosaccharides and other six-membered rings. Substances like glucose exhibit this preference, with bulky groups in the equatorial positions, providing greater stability to the molecule. In macrostructures like cellulose and starch, the positioning of these groups can significantly affect the physical properties of the material.
Drawing chair conformations of cyclohexane and its substituted variants helps us predict the stability of molecules based upon the axial or equatorial positioning of the substituents. Therefore, chemists often place bulky substituents in the equatorial position to maintain a low-energy, stable conformation.