Gauche Conformation of butane is:
Gauche Conformation of butane is:
The correct option is B
Conformations of butane: As the alkane molecule becomes larger, the conformation situation becomes more complex. In butane CH3−CH2−CH2−CH3, for example, the rotation about the single bond between two inner atoms C2 and C3 is considered. In this case, all the staggered as well as eclipsed conformations will not have same stability and energy because of different types of interaction between C - C (of methyl) and C - H bonds.
The lowest energy conformation will be the one, in which the two methyl groups are as far apart as possible i.e., 180∘ away form each other.
This conformation will be maximum staggered and is called anti conformation .
As is clear from the above Newman projection the Gauche or Skew conformations ( are also staggered. However, in these conformations, the methyl groups are so close that they repel each other.
Conformations of butane: As the alkane molecule becomes larger, the conformation situation becomes more complex. In butane CH3−CH2−CH2−CH3, for example, the rotation about the single bond between two inner atoms C2 and C3 is considered. In this case, all the staggered as well as eclipsed conformations will not have same stability and energy because of different types of interaction between C - C (of methyl) and C - H bonds.
The lowest energy conformation will be the one, in which the two methyl groups are as far apart as possible i.e., 180∘ away form each other.
This conformation will be maximum staggered and is called anti conformation .
As is clear from the above Newman projection the Gauche or Skew conformations ( are also staggered. However, in these conformations, the methyl groups are so close that they repel each other.
