JEE Main · 2024 · 27 Jan 2024 · Shift 2 · General Organic Chemistry

Rotation about the C–C single bond in ethane can occur through any angle, so there are, in principle, an infinite number of conformations. In the staggered form the H–C–C–H dihedral angle between substituents on the two carbons is $60^{\circ }$. Torsional strain from eclipsing C–H bonds is at a minimum in the staggered form and at a maximum in the eclipsed form, so the staggered conformation — not the eclipsed one — is the most stable; the claim that eclipsed is most stable is false. All conformations interconvert freely by rotation about the C–C bond at room temperature.