If the third member of a homologous series is C3H8, the fifth member will be
Answer Details
A homologous series is a series of organic compounds having the same functional group and similar chemical properties in which the successive members differ by a CH2 unit. So, the general formula of the homologous series would be CnH2n+2. If the third member of a homologous series is C3H8, it means that the general formula of the series is CnH2n+2, where n = 3. C3H8 belongs to the alkane series, so the fifth member of the series would also belong to the alkane series and have the general formula CnH2n+2, where n = 5. Substituting n = 5 in the general formula, we get C5H2(5)+2 = C5H12. Therefore, the fifth member of the homologous series would be C5H12.