2-methylbutan-2-ol is an example of a

Correct answer: Tertiary alkanol

Explanation: The class of an alkanol depends on how many carbon groups are attached to the carbon bearing the –OH. In 2-methylbutan-2-ol, the –OH is on carbon 2, which is also bonded to three alkyl groups (a methyl, another methyl, and an ethyl). A carbon with three alkyl substituents carrying the –OH defines a tertiary (3°) alkanol.

• Dihydric alkanol — Incorrect. Would have two –OH groups; here there is only one.
• Tertiary alkanol — Correct.
• Secondary alkanol — Incorrect. A 2° alcohol has the –OH carbon attached to two alkyl groups.
• Primary alkanol — Incorrect. A 1° alcohol has the –OH carbon attached to one alkyl group.