Question
Alkanes with even carbon atoms have higher melting points than alkanes with an odd number of carbon atoms.Explain.
Solution
This is because alkane chains with an even number of the carbon atoms (more symmetrical) pack more closely than those with an odd number of carbon atoms (less symmetrical) in the crystalline state. 
As a result, attractive forces between the individual chains of an alkane with an even number of carbon atoms are greater and thus the melting point is higher.
