CIE iGCSE Co-Ordinated Science C11.2 Naming organic compounds Exam Style Questions Paper 1

In organic chemistry, the ending of a compound’s name indicates the type of compound:

• -ane ending indicates an alkane (a saturated hydrocarbon with only single carbon-carbon bonds).
• -ene ending indicates an alkene (an unsaturated hydrocarbon containing at least one carbon-carbon double bond).
• -ol ending indicates an alcohol (contains an -OH group).

Looking at each structure:

• A: \( \text{CH}_4 \) (methane) — only single bonds, so -ane.
• B: \( \text{C}_2\text{H}_5\text{OH} \) (ethanol) — contains an -OH group, so -ol.
• C: \( \text{C}_2\text{H}_6 \) (ethane) — only single bonds, so -ane.
• D: \( \text{C}_2\text{H}_4 \) (ethene) — contains a carbon-carbon double bond (C=C), so -ene.

Therefore, the structure that represents a compound with a name ending in ‘ene’ is Structure D.

✅ Answer: (D)