The two successive members in a homologous series differ from each other by which group?

Correct option is A

The correct answer is (a) -CH₂-.
Explanation:
In a homologous series, each successive member differs from the previous one by a -CH₂- group. This means that the molecular formula of each member increases by a unit of CH₂. For example, in the alkane series:
· Methane (CH4​) → Ethane (C2H6) → Propane (C3H8​) → Butane (C4H10), and so on.
Each member has one more -CH₂- group than the previous one. This regular difference in molecular structure is a defining characteristic of homologous series.
Information Booster:
· A homologous series is a group of organic compounds with a similar general formula and chemical properties.
· Members of a homologous series show a gradual variation in physical properties, such as boiling and melting points, due to the increasing molecular size.
· Examples of homologous series include alkanes (CnH2n+2​), alkenes (CnH2n​), and alkynes (CnH2n−2​).
· Homologous series are important in organic chemistry for classifying and studying compounds systematically.
· The -CH₂- difference results in a molar mass increment of 14 g/mol for each successive member.