What is pyrolysis or cracking? Explain with example.
The decomposition of a compound by heat in the absence of air is called Pyrolysis. When pyrolysis occurs in alkanes, the process is termed as cracking.
For example:
Alkanes on heating under high temperature or in the presence of a catalyst in absence of air broken down into lower alkanes, alkenes and hydrogen.
$$C_3H_8\xrightarrow{higher\ temp} C_2H_4+CH_4$$