Q1. [1] § 4.2.2 Chains, Branches and Rings § 4.2.4 Homologous Series § 4.2.5 Nomenclature of Carbon Compounds
Consider the following statements about homologous series of carbon compounds :
(a) All succeeding members differ by – CH₂ unit.
(b) Melting point and boiling point increases with increasing molecular mass.
(c) The difference in molecular masses between two successive members is 16 u.
(d) C₂H₂ and C₃H₄ are NOT the successive members of alkyne series.
The correct statements are –
- (A) (a) and (b)
- (B) (b) and (c)
- (C) (a) and (c)
- (D) (c) and (d)
Previously asked in CBSE board exam
2024 31/2/1 Q7
Generated by claude-sonnet-4-6 · 2026-06-15 06:50 · grounding rag
Model Answer
(A) (a) and (b)
Successive members of a homologous series differ by –CH₂ (14 u, not 16 u), and melting/boiling points increase with molecular mass.
Explanation
Statement (c) is wrong — the mass difference is 14 u (CH₂), not 16 u. Statement (d) is wrong — C₂H₂ and C₃H₄ are indeed successive alkynes (differ by –CH₂). Statements (a) and (b) are directly supported by the textbook passage on homologous series.
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