Draw Newman and sawhorse projections for the eclipsed and staggered conformations of ethane. Which of these conformations is more stable and why ?

Explanation

Staggered form of ethane is more stable than the eclipsed conformation by about 12.55 KJ/mol. This is because any two hydrogen atoms on adjacent carbon atoms of staggered conformation are maximum apart while in eclipsed conformation, they cover or eclipse each other in space. Thus in staggered form, there is minimum repulsive forces, minimum energy and maximum stability of the molecule.