What effect the branching of an alkane has on its boiling point?

Explanation

In general , as the branching increases, the packing of the molecules in the crystal lattice becomes less close and hence the m.p. decreases accordingly. However , if the branching makes the molecule symmetrical , the packing of the molecules in the crystal lattice becomes close and hence the m.p. increases. Now since isopentane is less symmetrical than n-pentane but neopentane is the most symmetrical of the three isomeric pentanes, therefore , the m.p. of isopentane (113 K) is lower than of n-pentane (143 K) but the m.p. of neopentane (256 K) is much higher than that of isopentane and n-pentane .