Concept:A tertiary alkanol has the carbon atom carrying the
−OH group bonded to three other carbon atoms.
Explanation:In 2-methylpentan-2-ol, the hydroxyl-bearing carbon is attached to a methyl group at C1, the methyl branch at C2, and the propyl chain at C3.
Thus, the central carbon is bonded to three carbon atoms, making this alcohol tertiary.
In the other options, the carbon attached to
−OH is connected to only one or two carbon atoms, so they are primary or secondary alkanols.
Answer:A. 2-methylpentan-2-ol