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 C_nH_2n+2. If the third member of a homologous series is C₃H₈, it means that the general formula of the series is C_nH_2n+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 C_nH_2n+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.