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

1. Analyze the question

The question asks us to classify the alcohol 2-methylpropan-2-ol based on its structure. To do this, we need to determine how many carbon atoms are directly attached to the carbon atom that holds the hydroxyl (-OH) group.

2. Explain the concept

Alkanols (alcohols) are classified based on the number of alkyl groups attached to the carbon atom bearing the -OH group:

• Primary ($1^\circ$) alkanol: The -OH group is attached to a carbon atom that is bonded to only one other carbon atom (or none, in the case of methanol).
• Secondary ($2^\circ$) alkanol: The -OH group is attached to a carbon atom that is bonded to two other carbon atoms.
• Tertiary ($3^\circ$) alkanol: The -OH group is attached to a carbon atom that is bonded to three other carbon atoms.

3. Show the solution

Let’s draw the structure of 2-methylpropan-2-ol:

1. Parent chain: "Propan" means 3 carbons in the main chain.
2. Position of -OH: "2-ol" means the -OH group is on the second carbon.
3. Substituent: "2-methyl" means a methyl group ($-CH_3$) is also on the second carbon.

The structure looks like this:

        CH3
         |
    CH3— C — CH3
         |
        OH

• Look at the central carbon atom (the one bonded to the -OH group).
• It is directly bonded to three other carbon atoms (one from the left, one from the right, and one from the methyl group above).
• Since the carbon bearing the -OH group is bonded to three other carbons, it is classified as a tertiary alkanol.

4. Identify the answer

Comparing our finding to the options provided: A. dihydric alkanol (Incorrect, it only has one -OH group) B. tertiary alkanol (Correct) C. secondary alkanol (Incorrect) D. primary alkanol (Incorrect)

5. Tip

Memory Trick: Think of the "T" in Tertiary as standing for Three. A tertiary carbon is always bonded to three other carbons. If you are ever confused, draw the structure out—it is the safest way to avoid mistakes in exams!