Which of the following pairs of compounds belongs to the same homologous series?

C₂H₆ and C₄H₁₀ belong to the same homologous series, which is the series of alkanes. The homologous series refers to a group of organic compounds that have similar structures and chemical properties, and the same functional group. They have a general formula, with the same difference in the number of carbon and hydrogen atoms between consecutive members. The alkanes are a homologous series of hydrocarbons with the general formula C_nH_2n+2. Therefore, C₂H₆ and C₄H₁₀ have different numbers of carbon atoms, but they both have only single bonds between the carbon atoms and hydrogen atoms.