Question

In carbinol system, sec-Butyl alcohol is named as ______.

• A. Ethyl methyl carbinol
• B. sec-Butylcarbinol
• C. Isopropyl carbinol
• D. Diethylcarbinol

Hint:

Always isolate the $C-OH$ core (the "carbinol" group) and mentally mask it. Whatever alkyl branches are sticking out of it become the prefix of your name.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks us to translate the common name of an alcohol ("sec-Butyl alcohol") into the older, derivative nomenclature system known as the "carbinol system."

Step 2: Detailed Explanation:
1. In the carbinol nomenclature system, the simplest alcohol, methanol ($CH_3OH$), is defined as the parent structural unit and is named "carbinol".
2. More complex alcohols are named as derivatives of carbinol by listing the names of the alkyl groups attached to the central carbon atom containing the -OH group.
3. Let's write the chemical structure of sec-Butyl alcohol (butan-2-ol):
$$CH_3 - CH(OH) - CH_2 - CH_3$$
4. Isolate the central "carbinol" carbon (the $-CH(OH)-$ unit).
5. Observe the substituent groups directly attached to this central carbinol carbon.
- On the left side, it is attached to a methyl group ($-CH_3$).
- On the right side, it is attached to an ethyl group ($-CH_2CH_3$).
6. Combine these alkyl group names alphabetically (or just sequentially as traditionally done) followed by the word "carbinol".
Thus, the name is Ethyl methyl carbinol.

Step 3: Final Answer:
The carbinol name is Ethyl methyl carbinol, matching option (a).