Answer:
Hexane > pentane > neopentane
Explanation:
The boiling point of alkanes varies with chain length. The greater the length of the chain, the greater its boiling point.
Since hexane consists of a longer chain than pentene, its boiling point is definitely higher than that of pentane.
Similarly, neopentane is a branched alkane, the boiling point of a branched alkane is always lower than that of its straight chain counterparts.