Question 3
For the following compounds, write structural formulas and IUPAC names for all possible isomers having the number of double or triple bond as indicated :
(a) C4H8 (one double bond)
(b) C5H8 (one triple bond)
The following structural isomers are possible for C4H8 with one double bond:

The IUPAC name of Compound
(I) is But-1-ene, Compound
(II) is But-2-ene, and Compound
(III) is 2-Methylprop-1-ene.
(b) The following structural isomers are possible for C5C8 with one triple bond:

The IUPAC name of Compound
(I) is Pent-1-yne, Compound
(II) is Pent-2-yne, and Compound
(III) is 3-Methylbut-1-yne.