The boiling points of three isomeric pentanes 1, 2 and 3 are

1) ${9.5}^{0}C$       2) ${28}^{0}C$     3) ${36}^{0}C$

If a compound have same m.f. but different chain isomer, then linear chain have higher boiling point and branched chains have lower boiling point. 

Then the boiling points of 3 isomeric pentane is-

$C{H}_3-C{H}_2-C{H}_2-C{H}_2-C{H}_3$

               n-pentane

         Boiling point = 36⁰C

Boiling point = 28⁰C

neo-pentane

         Boiling point = 9.5⁰C