Which of the following represents the corrcet `IUPAC` name for the compounds concerned?
a. 2,2-Dimethy1 pentane or 2-Dimethy1 pentane
b. 2,4,7-Trimethy1octane or 2,5,7-Trimethyloctane
c. 2-Chloro-4-methy1pentane or 4-Chloro-2-melthypentane
d. But-3-yn-1-ol or But-4-ol-1-yne

Explanation

(a) 2, 2-Dimethylpentane. For two alkyl groups on the same carbon its locant is repeated twice, (b) 2, 4, 7-Trimethyloctane since 2, 4, 7-locant set is lower than 2, 5, 7. (c) 2-Chloro-4-methylpentane. Alphabetical order of substituents. (d) But-3-yn-1-ol. Lower locant for the principle functional group i.e., alcohol.