The number of compounds given below that belong to same homologous series are
CH2O2, C3H8O, C2H4O2, C2H6, C3H6O2, C5H10O2, C3H8
4
Homologogous series is a series of compounds having the same functional group and the successive members of which differ by -CH2 group.
HCOOH(CH2O2), CH3COOH(C2H4O2), CH3CH2COOH(C3H6O2), CH3CH2CH2CH2COOH(C5H10O2)