Question

Draw each molecule in a stable chair conformation and indicate whether each red group is axial or equatorial.

Short answer

The carbon-hydrogen bonds in cyclohexane are of two types, that is, axial and equatorial. The equatorial bonds or hydrogens lie about the equator of cyclohexane ring or in the plane of the ring. The axial bonds project perpendicular to the plane of the ring. Cyclohexane is not a static structure, that is, it can undergo conformational inversion from one chair form to another. In the conformational inversion, the equatorial hydrogens become axial or vice-versa.

Step-by-step solution

Step-1. Axial and equatorial bonds in cyclohexane:

The carbon-hydrogen bonds in cyclohexane are of two types, that is, axial and equatorial. The equatorial bonds or hydrogens lie about the equator of cyclohexane ring or in the plane of the ring. The axial bonds project perpendicular to the plane of the ring. Cyclohexane is not a static structure, that is, it can undergo conformational inversion from one chair form to another. In the conformational inversion, the equatorial hydrogens become axial or vice-versa.

Step-2. Depiction of given molecules in stable chair conformation:

The given molecules are shown in their stable chair conformation and axial and equatorial bonds or hydrogens or groups are abbreviated as “ax” for axial and “eq” for equatorial in the diagrams. Stable chair conformation means, which is free from any strain like torsional strain or angular strain in the molecule.