International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

Disable ads (and more) with a membership for a one time $4.99 payment

Prepare for the IGCSE Chemistry Exam with our comprehensive quiz. Practice with multiple choice questions and detailed explanations to boost your understanding. Excel in your examination journey!

Practice this question and more.


What is produced in addition to shorter chain hydrocarbons during cracking?

  1. Alcohols

  2. Alkenes

  3. Acids

  4. Ethers

The correct answer is: Alkenes

During the process of cracking, larger hydrocarbon molecules, typically obtained from crude oil, are broken down into shorter chain hydrocarbons. This process primarily produces alkenes as one of its key products. Alkenes are unsaturated hydrocarbons that contain at least one double bond between carbon atoms. Their formation occurs when the carbon chain of the original larger hydrocarbon fragments, resulting in the release of smaller molecules that can include shorter chain hydrocarbons and various alkenes. For example, when cracking occurs on a hydrocarbon chain, smaller compounds like ethylene (an alkene) can be produced along with other shorter-chain alkanes. The other options—alcohols, acids, and ethers—are not major products typically associated with the cracking process. While alcohols can be produced by other means, such as fermentation or hydration reactions, they do not arise directly from the cracking of hydrocarbons. Similarly, acids and ethers are not commonly produced during the cracking process, which focuses primarily on the production of simple hydrocarbons and alkenes. Thus, the correct identification of alkenes highlights their significant role as a product of cracking processes.