What is a saturated hydrocarbon?

• A. A hydrocarbon with single bonds between carbon atoms.
• B. A hydrocarbon containing at least one double bond.
• C. A hydrocarbon that contains benzene rings.
• D. A hydrocarbon with triple bonds.

Answer: (A)

Understanding saturated hydrocarbons centers on the bonds between carbon atoms. A saturated hydrocarbon has only single bonds between carbon atoms, so each carbon forms four single bonds and the molecule carries as many hydrogens as possible (general formula CnH2n+2 for acyclic alkanes). This is what makes hydrocarbons saturated. If there is a double or triple bond, or an aromatic ring, the hydrocarbon is unsaturated because those multiple bonds limit hydrogen attachment and allow further reactions. So the description of a hydrocarbon with only single bonds between carbon atoms is the one that fits a saturated hydrocarbon.