Which conformation(s)show(s)the bromines in a gauche orientation for 2,3-dibromobutane,viewed through the C-2-C-3 bond?

Question

Quizplus · Accepted Answer

In both conformations I and V, the two bromine atoms are on opposite sides of the C-2-C-3 bond, which is designated as the trans conformation. The trans conformation is equivalent to the gauche conformation because the two bromine atoms are close together and protrude from the central carbon atoms with a torsion angle of approximately 60 degrees. Conformations III and IV in which the bromine atoms are on the same side of the molecule are designated as the gauche conformation. Conformation II, on the other hand, indicates an anti conformation because the two bromine atoms reside on opposing sides of the carbon chain.

Which Conformation(s)show(s)the Bromines in a Gauche Orientation for 2,3-Dibromobutane,viewed Through