已知某烷烃分子中的电子数为42

C5H12有三个异构体：正戊烷、异戊烷、新戊烷。 CH3?CH2?CH2?CH2?CH3 正戊烷 CH3 | CH3?CH?CH2?CH3 异戊烷 CH3 | CH3?C?CH3 新戊烷 (沸点最低) | CH3