Arrange the following Newman projections of butane in order of energy.
A) I

Question

Arrange the following Newman projections of butane in order of energy. 
A) I<III<II<IV 
B) IV<II<III<I 
C) III<I<IV<II 
D) II<IV<I<III

Quizplus · Accepted Answer

Newman projection I has the lowest energy because the methyl groups are in the anti position, which minimizes steric hindrance. Newman projection III has the next lowest energy because one methyl group is in the gauche position, causing some steric hindrance. Newman projection II has higher energy than III because both methyl groups are in the gauche position, causing more steric hindrance. Newman projection IV has the highest energy because the methyl groups are in the eclipsed position, causing maximum steric hindrance. Therefore, the correct order is I<III<II<IV.

Arrange the Following Newman Projections of Butane in Order of Energy