See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Concept: Homologous series is a group of organic compounds that share the same general formula, have similar chemical properties, and differ from each other by a repeating unit (usually -CH2-). Reasoning: Members of a homologous series all fit the same general formula. For example, alkanes have the general formula CnH(2n+2), alkenes CnH2n, alkynes CnH(2n-2), etc. Each successive member differs by one CH2 unit. Why other options fail: - (b) Empirical formula: Members of a homologous series generally do NOT share the same empirical formula. For example, methane CH4 has empirical formula CH4, ethane C2H6 has empirical formula CH3, propane C3H8 has empirical formula C3H8 — these differ. - (c) Structural formula: Different members have different structural formulas since they differ by CH2 units and thus have different chain lengths and arrangements. - (d) Molecular formula: Each member has a different molecular formula (e.g., CH4, C2H6, C3H8 for alkanes), so they do not share the same molecular formula. The defining characteristic of homologous compounds is that they share the same general formula. Therefore, the correct answer is A.