Question

The I.U.P.A.C. name of CH₃.C ≡ C. CH (CH₃)₂ is 

(a) 4-methyl-2-pentyne 

(b) 4, 4'-dimethyl-2-butyne

(c) methylisopropylacetylene  

(d) 2-methyl-4-pentyne

Answer 1

Correct option is (a) 4-methyl-2-pentyne 

\(H_3 C - C \equiv C - CH < ^{CH_3}_{CH_3}\) is the required structure.

Now, we start numbering from the leftmost carbon as by doing that, the triple bond will be on 2^nd carbon.

Hence, the name of the compound will be 4 methyl-2-pentyne as there are 5 carbons on the parent chain.