Question

Rank the following molecules using numbers 1 - 4 in order of increasing boiling points (i.e. you would input 1 for the molecule with the lowest boiling point.)

A. decane
B. 3,3,4,4-tetramethylhexane
C. 2,2-dimethylpropane
D. dodecane

Answer 1

B<C<A<D

Step-by-step explanation:

The boiling point of alkanes increases with increasing chain length. Heavily branched alkanes usually show lower boiling points because of smaller dispersion forces. The longer the hydrocarbon chain, the higher the expected boiling point due to greater dispersion forces. This accounts for the order of increasing boiling points stated. Dodecane, a long chain alkanes us expected to have the highest boiling point, filled by decane then the di substituted before the tetra substituted alkanes which has the lowest boiling point.