How many structural isomers can be drawn for pentane (C5H12)?

1 Answer
Mar 2, 2018

Are there not THREE structural isomers with formula #C_5H_12#?

Explanation:

#(i)# #"H"_3"CCH"_2"CH"_2"CH"_2"CH"_3# #"n-pentane"#.

#(ii)# #"H"_3"CCH"("CH"_3)"CH"_2"CH"_3# #"isopentane"#.

#(iii)# #"H"_3"CC"("CH"_3)_3# #"neopentane"#.

The normal boiling points of these isomers are respectively: #36.1# #""^@C#; #27.7# #""^@C#; #9.5# #""^@C#.

Why does the length of the carbon chain apparently affect the boiling point?