Final answer:
The anti conformation for butane is the staggered conformation, where the largest groups are farthest apart on adjacent carbons, minimizing steric hindrance and resulting in greater stability.
Step-by-step explanation:
The student has asked about the anti conformation of butane. The correct answer to which conformation represents the anti conformation for butane is the staggered conformation. This is because, in the staggered conformation, the most significant groups (such as the -CH3 groups in butane) are positioned the furthest apart which lowers their steric hindrance, leading to a more stable structure. The anti conformation is indeed a type of staggered conformation where the two largest groups are 180° apart on adjacent carbons, as seen when viewing the C2-C3 bond in butane. This is different from the eclipsed conformation, which is a higher energy state where the groups are aligned, causing greater steric strain.
Other conformations mentioned, such as the chair and boat conformations, pertain to cyclohexane, not butane, and thus are not relevant to the concept of anti conformation in the context of linear alkanes like butane. Therefore, among the given options, only the staggered conformation is synonymous with the anti conformation for butane.