AP BIOLOGY

Detailed explanation-1: -Generally, Butane has four conformation isomers which are fully eclipsed, gauche, eclipsed, and anti butane conformational isomers.

Detailed explanation-2: -As with ethane, the staggered conformations of butane are energy ‘valleys’, and the eclipsed conformations are energy ‘peaks’. However, in the case of butane there are two different valleys, and two different peaks.

Detailed explanation-3: -The anti-conformation of n-butane is the most stable conformer of n-butane.

Detailed explanation-4: -Conformation refers to the spatial arrangements of bonds which can be adopted by a molecule when the bond rotation takes place. There are 4 types of generally known conformations namely; eclipsed, staggered, anti and gauge conformations. These conformations also give arise to conformational isomerism.

Detailed explanation-5: -If we rotate the front, (blue) carbon by 60°clockwise, the butane molecule is now in a staggered conformation. This is more specifically referred to as the ‘gauche’ conformation of butane. Notice that although they are staggered, the two methyl groups are not as far apart as they could possibly be.