When alkanes are cracked, they break down into smaller molecules. The products of cracking can include:

* Alkanes: Smaller alkanes are often formed.

* Alkenes: These are unsaturated hydrocarbons with a double bond, and their formation is a key characteristic of cracking.

* Hydrogen: This is a common byproduct of cracking.

Examples:

* Cracking of Hexane (C6H14):

* C6H14 → C4H10 + C2H4 (Butane + Ethene)

* Cracking of Octane (C8H18):

* C8H18 → C6H14 + C2H4 (Hexane + Ethene)

* C8H18 → C4H10 + C4H8 (Butane + Butene)

Therefore, the compound that may be formed when alkanes are cracked is an alkene (like ethene, propene, butene, etc.).