Alkyl halides (monohaloalkanes) form a homologous series. Which general formula represents this series? (X = halogen atom)
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → \( \ce{C_nH_{2n+1}X} \)
An alkyl halide is an alkane in which one hydrogen atom is replaced by a halogen. An alkane is CnH2n+2; removing one H leaves the alkyl group CnH2n+1, and the halogen takes its place: CnH2n+1X. For example, n = 1 gives CH3Cl and n = 2 gives C2H5Br.
NCERT (2026-27 edition):
6.1.2 Compounds Containing sp3 C—X Bond (X= F, Cl, Br, I) – “(a) Alkyl halides or haloalkanes (R—X) … In alkyl halides, the halogen atom is bonded to an alkyl group (R). They form a homologous series represented by CnH2n+1X.”