Write the molecular formula of the 2nd and 3rd member of the homologous series where the first member is ethyne.
The general formula for the homologous series whose first member is ethyne is CnH2n - 2.
The two consecutive members (2nd and 3rd) of this series are:
a. CH3C≡CH (Propyne); where n is 3
b. CH3CH2C≡CH(1-Butyne) or CH3C≡CCH3 (2-Butyne); where n is 4
The molecular formulae are C3H4 and C4H6, respectively.