In the following structures, which one is having staggered conformation with maximum dihedral angle?

Explanation: Newman projections represent conformations by viewing directly along a carbon-carbon bond.

In an eclipsed conformation, bonds on the front carbon overlap with those on the back carbon, giving a dihedral angle of $$0^\circ$$.

In a staggered conformation, the bonds are separated by $$60^\circ$$.

For butane, the dihedral angle is measured between the two $$-CH_3$$ groups.

In Option A, the two methyl groups overlap, so the conformation is eclipsed with a dihedral angle of $$0^\circ$$.

In Option B, the two methyl groups are opposite to each other in a staggered arrangement.

This is the anti conformation, where the methyl groups are separated by the maximum possible angle $$180^\circ$$

In Option C, the conformation is staggered, but the two methyl groups are separated by only $$60^\circ$$.

This arrangement is called the gauche conformation.

In Option D, the conformation is eclipsed. The methyl groups are separated by $$120^\circ$$.

However, because the bonds are eclipsed, it is not a staggered conformation.

Therefore, Option B represents the staggered conformation with the maximum dihedral angle.