Rotation about the C2-C3 bond of butane gives anti (A), gauche (G), partially eclipsed (P, a CH3 eclipsing H) and fully eclipsed (F, CH3 eclipsing CH3) conformations. The order of increasing potential energy is:

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JEE Main levelSingle correct optionDifficulty 2 of 3hc173

Rotation about the C2-C3 bond of butane gives anti (A), gauche (G), partially eclipsed (P, a $CH X_{3}$ eclipsing H) and fully eclipsed (F, $CH X_{3}$ eclipsing $CH X_{3}$ ) conformations. The order of increasing potential energy is:

AA < G < P < F
BG < A < P < F
CA < P < G < F
DA < G < F < P

Answer: A

Anti has the methyl groups farthest apart and is the global minimum. Gauche has steric repulsion between methyls and lies a little higher. Staggered forms are lower than eclipsed ones, and the fully eclipsed form with two methyls opposed is the maximum.

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Rotation about the C2-C3 bond of butane gives anti (A), gauche (G), partially eclipsed (P, a CHX3​ eclipsing H) and fully eclipsed (F, CHX3​ eclipsing CHX3​) conformations. The order of increasing potential energy is:

Answer: A

More questions on Alkanes: preparation (Wurtz, Kolbe, decarboxylation) and reactions

Rotation about the C2-C3 bond of butane gives anti (A), gauche (G), partially eclipsed (P, a $CH X_{3}$ eclipsing H) and fully eclipsed (F, $CH X_{3}$ eclipsing $CH X_{3}$ ) conformations. The order of increasing potential energy is: