Name the two types of cracking that can occur with hydrocarbons.

The correct answer identifies thermal cracking and catalytic cracking as the two primary methods of breaking down larger hydrocarbon molecules into smaller, more useful ones.

Thermal cracking involves breaking the carbon-carbon bonds in hydrocarbons using high temperatures and pressures. This method can yield a variety of products, including olefins and paraffins, but often results in a mix of products which may require further processing.

Catalytic cracking, on the other hand, employs a catalyst to enhance the reaction process at lower temperatures and pressures. This method is particularly favored in the petroleum industry because it produces higher yields of more desirable products, such as gasoline and diesel, with better quality.

While other terms, like hydrocracking, refer to specific methods that use hydrogen to stabilize products formed during cracking, the primary methods recognized in the petrochemical industry remain thermal cracking and catalytic cracking. The incorrect choice specifies steam cracking, which is a variation where steam is used alongside heat, but it's distinct from the main forms generally covered in a GCSE Chemistry context.