Haloalkanes and Haloarenes – JEE Main 2026 Quiz

Q1. The correct statement regarding nucleophilic substitution reaction in a chiral alkyl halide is:

Retention occurs in SN1 and inversion in SN2 Racemisation occurs in SN1 and inversion occurs in SN2 Racemisation occurs in both SN1 and SN2 Inversion occurs in SN1 only

Q2. 2-Chlorobutane reacts with Cl₂ to give C₄H₈Cl₂ isomers. Total number of optically active isomers formed is:

4 5 6 8

Q3. 151 g of 2-bromopentane undergoes elimination with alcoholic KOH giving alkene P (80% yield), which reacts with Br₂ (100%). Mass of final product obtained is:

168 g 184 g 200 g 160 g

Q4. The isomeric deuterated bromide (C₄H₈DBr) having two chiral carbon atoms is:

2-Bromo-1-deuterobutane 2-Bromo-1-deutero-2-methylpropane 2-Bromo-3-deuterobutane 2-Bromo-2-deuterobutane

Q5. Among the following, compound having maximum number of chlorine atoms is:

Gammaxene Chloropicrin Chloral Freon-12

Q6. The pair having non-zero dipole moment in both compounds is:

cis-butene, trans-butene CH₂Cl₂, CHCl₃ Benzene, anisidine 1,4-dichlorobenzene, 1,3-dichlorobenzene

Q7. Propane on chlorination gives two dichloro products x and y. x is optically active. Number of trichloro products formed from x is:

4 2 3 5

Q8. Alkyl halide is converted into alkyl isocyanide by reaction with:

KCN NH₄CN NaCN AgCN

Q9. The alkyl halide that forms the most stable carbocation during SN1 reaction is:

Allyl bromide Triphenylmethyl bromide Ethyl bromide Methyl bromide

Q10. Ethylbenzene is converted into p-bromostyrene. Correct reagent sequence is:

Cl₂/AlCl₃ → Br₂/Fe → alc. KOH Cl₂/Fe → Br₂/AlCl₃ → aq. KOH Br₂/Fe → Cl₂, Δ → alc. KOH Br₂/H₂O → KOH

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Theory: Haloalkanes and Haloarenes (JEE Main 2026)

Haloalkanes and haloarenes are organic compounds containing halogen atoms (F, Cl, Br, I) bonded to aliphatic or aromatic carbon atoms respectively. Haloalkanes generally undergo nucleophilic substitution and elimination reactions, whereas haloarenes show electrophilic substitution reactions due to resonance stabilisation of the aromatic ring.

Nucleophilic substitution reactions occur mainly by SN1 and SN2 mechanisms. SN1 involves carbocation formation and leads to racemisation in chiral molecules, whereas SN2 occurs via backside attack resulting in inversion of configuration. Stability of carbocation plays a major role in determining the reaction pathway.

Elimination reactions occur in the presence of alcoholic KOH leading to formation of alkenes following Zaitsev’s rule. In haloarenes, halogens are ortho-para directing but deactivating due to their −I and +R effects.

Haloalkanes are also important intermediates in preparation of alcohols, alkenes, nitriles, isocyanides, and organometallic compounds. Understanding stereochemistry, reaction mechanisms, and physical properties is crucial for JEE Main 2026.