Part I: SP3 Hybridization: B: Ethane Distance between C-C in ethane: Distance between H atoms in eclipsed conformation: Distance between H atoms in staggered conformation: Which is more stable (circle one): STAGGERED or ECLIPSED

Distance between C-C in ethane- 1.54 Å

Distance between H atoms in eclipsed conformation-2.3 Å

Distance between H atoms in staggered conformation- 2.5 Å

Staggered conformation is more stable

Explanation:

The staggered conformation of ethane can be demonstrated as the most stable of conformation of ethane, because the angles between Carbon-Hydrogen bonds in both the front and back carbon atoms are maximized.  This now minimizes the energy of this conformation compared to the eclipsed conformation.

Considering the eclipsed conformation, it is obvious that the electron densities on Carbon-Hydrogen bonds come very close together thereby bringing two C-H bonds  into a dihedral angle of almost zero degrees. This causes their electron clouds to experience strong repulsion, thereby raising the molecules's total energy.