Given the following Newman projection of ethane looking down the $C–C$ bond, which of the following wedge and dash structures correctly represents the same conformation?

• A. The front carbon has a $\mathrm{CH}{3}_{}$ group on a dash, a $H$ on a wedge, and a $H$ in the plane; the back carbon has a $\mathrm{CH}{3}_{}$ group on a wedge, a $H$ on a dash, and a $H$ in the plane.
• B. Both the front and back carbons have all $H$ in the plane.
• C. The front carbon has a $\mathrm{CH}{3}_{}$ group on a wedge, a $H$ on a dash, and a $H$ in the plane; the back carbon has a $\mathrm{CH}{3}_{}$ group on a dash, a $H$ on a wedge, and a $H$ in the plane.
• D. The front carbon has a $H$ on a wedge, a $\mathrm{CH}{3}_{}$ group on a dash, and a $H$ in the plane; the back carbon has all $H$ in the plane.

Answer: (C)

Verified step by step guidance

1. Identify the Newman projection's perspective: you are looking down the C–C bond of ethane, so the front carbon is closest to you and the back carbon is behind it.
2. Recall that in wedge-dash notation, wedges represent bonds coming out of the plane towards the viewer, dashes represent bonds going behind the plane, and lines in the plane are flat on the paper.
3. Analyze the Newman projection substituents on the front carbon: determine which groups are staggered or eclipsed relative to the back carbon substituents, and assign wedge, dash, or plane accordingly to maintain the correct 3D orientation.
4. Do the same for the back carbon substituents, ensuring that the relative positions of the groups match the Newman projection's conformation when viewed from the front carbon's perspective.
5. Confirm that the spatial arrangement of the methyl (CH₃) groups and hydrogens on both carbons in the wedge-dash structure corresponds exactly to the Newman projection's conformation, preserving the correct stereochemistry and bond angles.