Which suffix indicates a saturated alkane in IUPAC nomenclature?

The suffix that indicates a saturated alkane in IUPAC nomenclature is -ane. Alkanes are hydrocarbons that contain only single bonds between carbon atoms, which makes them saturated, meaning they have the maximum number of hydrogen atoms possible. The use of -ane specifically designates these single-bonded carbon chains.

In contrast to -ane, the suffix -ene denotes alkenes, which are unsaturated hydrocarbons that contain at least one carbon-carbon double bond. The suffix -yne refers to alkynes, which contain one or more carbon-carbon triple bonds, also indicating unsaturation. Lastly, the suffix -al indicates aldehydes related to carbonyl functional groups (-CHO), and it's not applicable to the classification of alkanes.

Thus, the identification of alkanes using the -ane suffix is critical for understanding and classifying organic compounds according to their bonding characteristics.