NEET UG – Haloalkanes & Haloarenes Chemistry Practice Paper 15 (PYQs)
NEET UG Chemistry Practice Paper – Part 15 (Haloalkanes & Haloarenes) is designed to strengthen students’ understanding of substitution and elimination mechanisms. This chapter is highly important for NEET due to its focus on SN1, SN2, E1, E2 reactions, reactivity trends, and name reactions, all of which are frequently tested. Total Questions: 30 | Total Marks: 120 Q1. Reactivity of alkyl halides towards SN1 follows: 1° > 2° > 3° 3° > 2° > 1° 2° > 3° > 1° All equal Tertiary carbocations are most stable. Q2. Which halogen is best leaving group? F Cl Br I I⁻ is weakest base and best leaving group. Q3. Which solvent favours SN1 reaction? DMSO Acetone Water Ether Polar protic solvents stabilise carbocation. Q4. Which reaction follows SN2 mechanism? Tertiary alkyl halide Primary alkyl halide Aryl halide Benzyl chloride (SN1 only) Less steric hindrance favours SN2. Q5. Which compound undergoes nucleophilic substitution most easily? CH₃Cl CH₃Br CH₃I CH₃F C–I bond is weakest. Q6. Aryl halides are less reactive because: sp³ hybridisation Resonance stabilisation Weak bond Strong +I effect Partial double bond character. Q7. Wurtz reaction gives: Alkene Alkane Alcohol Ketone Coupling reaction using Na in dry ether. Q8. Which reaction forms alcohol from alkyl halide? KCN Aqueous KOH NaNH₂ Zn Nucleophilic substitution. Q9. Which alkyl halide gives maximum elimination? Primary Secondary Tertiary Methyl Tertiary favours E1/E2. Q10. Which compound reacts fastest with alcoholic KOH? CH₃Cl C₂H₅Cl (CH₃)₃CCl C₆H₅Cl Tertiary favours elimination. Q11. Sandmeyer reaction converts: Alkyl halide to amine Diazonium salt to aryl halide Alcohol to alkene Alkene to alcohol Cu salts replace diazonium group. Q12. Finkelstein reaction is used to prepare: Alkyl fluoride Alkyl chloride Alkyl bromide Alkyl iodide NaI in acetone. Q13. Which halide gives positive carbylamine test? Primary amine Secondary amine Tertiary amine Amide Primary amines give foul smell. Q14. Which compound is most reactive in nucleophilic substitution? Vinyl chloride Allyl chloride Chlorobenzene Methyl chloride Resonance stabilises intermediate. Q15. Which compound forms Grignard reagent? Aryl halide Alkyl halide Vinyl halide All of these RMgX formed from alkyl halides. Q16. Which compound undergoes hydrolysis fastest? CH₃Cl C₂H₅Cl (CH₃)₃CCl C₆H₅Cl Tertiary carbocation stable. Q17. Which halogen has strongest C–X bond? C–F C–Cl C–Br C–I C–F bond is strongest. Q18. Which reagent is used to prepare alkyl fluoride? AgF NaI KBr ZnCl₂ Swarts reaction. Q19. Which alkyl halide undergoes SN2 fastest? Tertiary Secondary Primary Aryl Less steric hindrance. Q20. Which compound does NOT undergo SN1? Tertiary alkyl halide Secondary alkyl halide Primary alkyl halide Benzyl halide Primary carbocation unstable. Q21. Which compound undergoes E2 reaction? With strong base With weak base With polar protic solvent Without base Strong base favours E2. Q22. Which reaction forms alkene from alkyl halide? Hydrolysis Elimination Addition Oxidation Alcoholic KOH. Q23. Which is most reactive towards nucleophile? Benzyl chloride Chlorobenzene Vinyl chloride Toluene Resonance stabilises carbocation. Q24. Which reagent gives elimination predominately? Aqueous KOH Alcoholic KOH Water NaCl Alcoholic medium favours elimination. Q25. Which reaction gives coupling product? Wurtz Sandmeyer Finkelstein Swarts Two alkyl groups couple. Q26. Which halide reacts fastest with NaI in acetone? Primary Secondary Tertiary Aryl SN2 favoured. Q27. Which compound undergoes nucleophilic aromatic substitution? Chlorobenzene Nitrobenzene p-Nitrochlorobenzene Toluene −NO₂ activates ring. Q28. Which halide forms alcohol via SN1? Tertiary Primary Vinyl Aryl Stable carbocation formed. Q29. Which is least reactive? Allyl chloride Benzyl chloride Chlorobenzene Tert-butyl chloride Resonance stabilised C–Cl bond. Q30. Haloalkanes are important because they: Undergo substitution Undergo elimination Form Grignard reagents All of these They are versatile intermediates. Submit Paper Conclusion: Why Part 15 (Haloalkanes & Haloarenes) Is Critical for Scoring in NEET Organic Chemistry The chapter Haloalkanes & Haloarenes is one of the most strategically important sections of Organic Chemistry for NEET aspirants. It connects foundational concepts from General Organic Chemistry with real reaction mechanisms, making it a bridge between theory and application. NEET UG Chemistry Practice Paper – Part 15 is carefully designed to strengthen this bridge and transform a potentially confusing chapter into a high-scoring opportunity. One of the biggest reasons this chapter matters is its heavy focus on reaction mechanisms. NEET frequently tests SN1, SN2, E1, and E2 mechanisms directly or indirectly. Students often struggle to differentiate when substitution will dominate and when elimination will occur. Through systematic practice in Part 15, learners clearly understand how substrate structure, solvent type, nucleophile strength, and leaving group ability influence the reaction pathway. This clarity dramatically improves accuracy in mechanism-based questions. Another key area covered in this paper is the stability of intermediates, especially carbocations. Since SN1 reactions depend on carbocation stability, questions often revolve around comparing tertiary, secondary, primary, allylic, and benzylic systems. Practicing such MCQs strengthens students’ ability to predict reactivity trends logically rather than guessing. This analytical approach is crucial for NEET, where subtle conceptual differences determine the correct option. The paper also reinforces understanding of leaving group ability and bond strength trends. Many students memorize that I⁻ is a better leaving group than Cl⁻ but fail to connect it to bond dissociation energy and stability of the leaving species. By solving structured questions in this practice set, students internalize these trends in a meaningful way, which helps them tackle unfamiliar variations in the exam. A particularly important section of this chapter involves aryl halides and their reduced reactivity. NEET frequently tests why chlorobenzene is less reactive toward nucleophilic substitution due to resonance stabilization and partial double bond character. Without conceptual clarity, students often confuse haloalkanes with haloarenes. Part 15 ensures that this distinction becomes crystal clear. The inclusion of name reactions such as Wurtz reaction, Finkelstein reaction, Swarts reaction, and Sandmeyer reaction further strengthens exam readiness. These reactions are commonly asked either directly or as part of multi-step conversion problems. Practicing them in MCQ format improves recall speed and reaction identification skills. Another major benefit of solving this practice paper is improved understanding of Grignard reagent formation and reactivity, one of the most important synthetic tools in Organic Chemistry. Even if detailed Grignard reactions appear later in the syllabus, mastering their origin in haloalkanes








