Question

Describe the conformers of n – butane.

Answer 1

1. Conformations of n-Butane:
   n-Butane may be considered as a derivative of ethane, as one hydrogen on each carbon is replaced by a methyl group
2. Eclipsed conformation:
   In this conformation, the distance between the two methyl group is minimum. So there is maximum repulsion between them and it is the least stable conformer.
3. Anti or staggered form:
   In this conformation, the distance between the two methyl groups is maximum and so there is minimum repulsion between them. And it is the most stable conformer.
4. The following potentially energy diagram shows the relative stabilities of various conformers of n-butane.

potential energy of a n-butane molecule as a funtion of the angle φ of bond rotation