Cracking is a petroleum refining process that breaks down large hydrocarbon molecules into smaller, more valuable ones. This process is typically carried out at high temperatures and pressures in the presence of a catalyst.

When a compound is cracked, the following may happen:

* The compound may break down into smaller hydrocarbons. This is the most common outcome of cracking, and it results in the production of gasoline, diesel fuel, and other petroleum products.

* The compound may form coke. Coke is a solid carbon deposit that can build up on the walls of the reactor vessel. This can lead to decreased efficiency and even equipment failure.

* The compound may undergo reforming. Reforming is a process that converts low-octane hydrocarbons into high-octane hydrocarbons. This is done by adding hydrogen to the hydrocarbons and then rearranging the molecular structure.

* The compound may undergo polymerization. Polymerization is a process that combines multiple molecules of a compound into a larger molecule. This process can be used to produce plastics and other polymers.

The specific reactions that occur during cracking depend on the composition of the feedstock and the reaction conditions.