What is meant by homologous series of organic compounds?

A series of organic compounds with the same general formula but differ from adjacent members by a –CH₂– group are referred to as homologous series of compounds. Members of the homologous series of functional group aldehyde are: 1. Ethanal : CH₃CHO 2. Propanal : CH₃CH₂CHO Physical properties: Determined by the hydrocarbon chain –CH₃ and –C₂H₅. Chemical properties: Determined by the functional group –CHO.