What is meant by cracking of alkanes ?

Breaking down of higher alkane into a mixture of lower alkanes and alkenes by heating or by the use of a catalyst is called cracking of alkanes.

For example, when hexane is heated strongly, it undergoes cracking to give butane and ethane.

There are two types of cracking:

(a) Thermal cracking: when a large molecule is cracked by heating alone atomic high temperature the process is termed thermal cracking.

(b) Catalyst cracking: when cracking is carried out by heating atomic relatively lower temperature in the presence of a suitable catalyst, the process is called catalyst cracking.