Final answer:
Sec-butyl alcohol is a secondary alcohol, identified by the hydroxyl group being attached to a carbon that is connected to two other carbon atoms.
Step-by-step explanation:
To determine which compound is a secondary alcohol, we look at where the hydroxyl group (-OH) is positioned on the carbon chain. In a secondary alcohol, this group is attached to a carbon atom that is also connected to two other carbon atoms.
Considering the two alternatives provided:
- Isobutyl alcohol
- Sec-butyl alcohol
The secondary alcohol among these is Sec-butyl alcohol. The 'sec' prefix in common nomenclature indicates that the hydroxyl group in sec-butyl alcohol is on a secondary carbon, which means this carbon is attached to two other carbons within the molecule. Isobutyl alcohol, on the other hand, has the hydroxyl group attached to a primary carbon atom that's connected to only one other carbon atom, classifying it as a primary alcohol.