Write the molecular formula of the 2nd and 3rd member of the homologous series whose first member is ethene.
The general formula for the homologous series whose first member is ethene is CnH2n.
The two consecutive members (2nd and 3rd) of this series are:
a. CH3CH=CH2 (Propene); where n is 3
b. CH3CH2CH=CH2(1-Butene) or CH3CH=CHCH3 (2-Butene); where n is 4
The molecular formulae are C3H6 and C4H8 respectively.