4:17 describe how long-chain alkanes are converted to alkenes and shorter-chain alkanes by catalytic cracking (using silica or alumina as the catalyst and a temperature in the range of 600–700⁰C)

Cracking involves the thermal decomposition of long-chain alkanes into shorter-chain alkanes and alkenes:

Conditions

Temperature: 600oC

Catalyst: aluminium oxide, Al2O3