Question

The correct IUPAC name for the given molecule should be ________.

• A. 4,4-dimethylbutan-2-ol
• B. 4-methylpentan-2-ol
• C. 2-methylpentan-4-ol
• D. 1,1-dimethylbutan-3-ol

Hint:

The priority for numbering is: Functional Group ($–OH$) > Substituent (Methyl).

Answer 1

The Correct Option is B

Step 1: Concept
IUPAC nomenclature for branched alcohols requires identifying the longest chain containing the $-OH$ group and numbering it to give the hydroxyl carbon the lowest possible number.
Step 2: Analysis
The structure is $CH_3-CH(OH)-CH_2-CH(CH_3)_2$. The longest continuous carbon chain containing the $-OH$ group has 5 carbons (pentane).
Step 3: Numbering
Numbering from the end closer to the $-OH$ group:

• Carbon 2 holds the hydroxyl ($-OH$) group.
• Carbon 4 holds a methyl ($-CH_3$) substituent.

Step 4: Conclusion
Combining the parts gives 4-methylpentan-2-ol.
Final Answer:(B)