Draw the Newman projections for the anti and gauche forms of 1,2-dibromoethane. The molecule has a dipole moment of 1.0 D.

a) Which form is responsible for the molecular dipole (gauche/anti)?

(b) Which conformation of 1,2-dibromoethane is present in the greatest amount at equilibrium (eclipsed/gauche/anti) (Hint: you always have more of the lower energy species at equilibrium)?

(c) Which of the following compounds has the larger energy barrier to internal rotation about the central bond? And why?