1. The problem is to identify the functional group present in alkanols. 2. Alkanols are a class of organic compounds derived from alkanes by replacing one hydrogen atom with a hydroxyl group. 3. The functional group characteristic of alkanols is the hydroxyl group, represented as $-OH$. 4. This group is attached to a saturated carbon atom (sp3 hybridized) in the alkane chain. 5. The presence of the $-OH$ group imparts properties such as polarity and the ability to form hydrogen bonds. 6. Therefore, the functional group for alkanols is the hydroxyl group $-OH$.