Answer: Ethyne is the first member of the alkyne homologous series.
The alkynes having four or more carbon atoms, the triple bond can be located in different positions along the chain, leading to the formation of structural isomers. They possess restricted rotation due to the triple bond and they do not have stereoisomers like the alkenes. The parent name of the alkyne has been taken from the IUPAC name for the alkane of the same number of carbon atoms, except the - ane ending is changed to - yne to indicate the presence of a triple bond.
Physical Properties of Alkyne
The physical properties of Alkyne are:
They are non-polar molecules with little solubility in polar solvents, such as water.
Alkynes of four or fewer carbon atoms tend to gas.
They have small dipole moments due to differences in electronegativity between the triple-bonded carbon atoms.
Which of the following is the first member of the alkyne homologous series?
Out of the given option, ethyne is the first member of the alkyne homologous series.