Which of the following reactions is characteristic of unsaturated hydrocarbons?
Correct: B
Unsaturated hydrocarbons (alkenes and alkynes) contain carbon-carbon double or triple bonds. These bonds are reactive and can 'open up' to accommodate additional atoms or groups, forming a saturated compound. This type of reaction is called an addition reaction. Saturated hydrocarbons (alkanes) primarily undergo substitution reactions. Combustion is a general reaction for most organic compounds, and esterification is a specific reaction between an alcohol and a carboxylic acid.