Ethyne is the member of alkyne series whose general formula is CnH2n−2 In CnH2n−2n= no. of atoms as 1, 2, 3... If n=2, then C2H2×2−2C2H2Ethyne If n=3, then C3H2×3−2C3H6−2C3H4Propyne So, the next member or homologue of ethyne is propyne (C3H4).