Which process breaks long-chain hydrocarbons into smaller units?

Which process breaks long-chain hydrocarbons into smaller units?

• A. Isomerization
• B. Hydrogenation
• C. Reforming
• D. Cracking

Answer: (D)

Cracking is the process that breaks long-chain hydrocarbons into smaller units. In refining, large molecules from crude oil are heated or catalyzed to cleave carbon–carbon bonds, producing shorter alkanes and alkenes that are suitable for fuels like gasoline. This step is essential to convert heavy fractions into lighter, more usable products. Isomerization rearranges atoms within the same molecule without shortening the chain, hydrogenation adds hydrogen to saturate unsaturated bonds rather than breaking the molecule, and reforming rearranges the carbon skeleton to improve properties like octane without primarily reducing chain length. So cracking best fits the idea of breaking big molecules into smaller ones.

Cracking is the process that breaks long-chain hydrocarbons into smaller units. In refining, large molecules from crude oil are heated or catalyzed to cleave carbon–carbon bonds, producing shorter alkanes and alkenes that are suitable for fuels like gasoline. This step is essential to convert heavy fractions into lighter, more usable products.

Isomerization rearranges atoms within the same molecule without shortening the chain, hydrogenation adds hydrogen to saturate unsaturated bonds rather than breaking the molecule, and reforming rearranges the carbon skeleton to improve properties like octane without primarily reducing chain length. So cracking best fits the idea of breaking big molecules into smaller ones.