Tiêu đề Haloalkanes & Haloarenes.pdf ✅

UNIT 3 HALOALKANES AND HALOARENES Exercise 1: NCERT Based Topic-wise MCQs 7.0 INTRODUCTION 1. Haloarenes contain halogen atom(s) attached to hybridised carbon atom. NCERT/Page-289 / N-159 (a) sp 3 (b) sp 2 (c) sp (d) both (a) and (b) 7.1 CLASSIFICATION 2. When two halogen atoms are attached to same carbon atom then it is: NCERT/Page-292 / N-162 (a) vic-dihalide (b) gem-dihalide (c) α, ω-halide (d) α, β-halide 3. Which of the following halide is 2 ∘ ? NCERT/Page-290 / N-160 (a) Isopropyl chloride (b) Isobutyl chloride (c) n-Propyl chloride (d) n-Butyl chloride 4. Which one of the following is not an allylic halide? NCERT Page N-160 (a) 4-Bromopent-2-ene (b) 3-Bromo-2-methylbut-1-ene (c) 1-Bromobut-2-ene (d) 4-Bromobut-1-ene 7.2 CLASSIFICATION 5. The IUPAC name of the compound shown below is NCERT Page-291 / N-161 (a) 2-bromo-6-chlorocyclohex-1-ene (b) 6-bromo-2-chlorocyclohexene (c) 3-bromo-1-chlorocyclohexene (d) 1-bromo-3-chlorocyclohexene 6. A compound is formed by substitution of two chlorine for two hydrogens in propane. The number of possible isomeric compounds is NCERT Page N-164 (a) 4 (b) 3 (c) 5 (d) 2 7. IUPAC name of (CH3 )3CCl is NCERT Page-291 / N-161 (a) 3-Chlorobutane (b) 2-Chloro-2-methylpropane (c) t-butyl chloride (d) n-butyl chloride
8. IUPAC name of CH3CH2C(Br) = CH − Cl is NCERT PAGE N- 162 (a) 2-bromo-1-chlorobutene (b) 1-chloro-2-bromobutene (c) 3-chloro-2-bromobutene (d) None of the above 9. Phosgene is a common name for NCERT PAGE N- 187 (a) phosphoryl chloride (b) thionyl chloride (c) carbon dioxide and phosphine (d) carbonyl chloride 7.3 NATURE OF C-X BOND 10. The main difference in C − X bond of a haloalkane and a haloarene is NCERT Page-312/N-182 a) haloalkanes are less reactive than haloarenes due to difficulty is C − X cleavage in haloalkanes. b) in haloalkanes the C attached to halagen in C − X bond is sp 3 hybridised while in haloarenes it is sp 2 hybridised. c) C − X bond in haloalkanes is shorter than haloarenes. d) C − X bond in haloarenes acquires a double bond character due to higher electronegativity of X than haloalkanes. 11. C − Cl bond of chlorobenzene in comparison to C − Cl bond in methyl chloride is NCERT Page-312 / N-182 (a) Longer and weaker (b) Shorter and weaker (c) Shorter and stronger (d) Longer and stronger 7.4 METHODS OF PREPARATION OF HALOALKANES 12. Halogenation of alkanes is NCERT PAGE N- 164 (a) a reductive process (b) an oxidative process (c) an isothermal process (d) an endothermal process 13. Ethylene dichloride can be prepared by adding HCl to NCERT Page N − 165 (a) ethane (b) ethylene (c) acetylene (d) ethylene glycol 14. The best method for the conversion of an alcohol into an alkyl chloride is by treating the alcohol with (a) PCl5 NCERT Page-294 / N-164 (b) dry HCl in the presence of anhydrous ZnCl2 (c) SOCl2 in presence of pyridine (d) none of these 15. Conant-Finkelstein reaction for the preparation of alkyl iodide is based upon the fact that NCERT Page-295/N-165 (a) sodium iodide is soluble in methanol, while sodium chloride is insoluble in methanol (b) sodium iodide is soluble in methanol, while NaCl and NaBr are insoluble in methanol (c) sodium iodide is insoluble in methanol, while NaCl and NaBr are soluble (d) the three halogens differ considerably in their electronegativity 16. Ethyl alcohol reacts with thionyl chloride in the presence of pyridine to give NCERT Page-294 / N-164
(a) CH3CH2Cl + H2O + SO2 (b) CH3CH2Cl + HCl (c) CH3CH2Cl + HCl + SO2 (d) CH3CH2Cl + SO2 + Cl2 17. Hydrocarbon (CH3 )3CH undergoes reaction with Br2 and Cl2 in the presence of sunlight, if the reaction with Cl is highly reactive and that with Br is highly selective so no.of possible products respectively is (are) (a) 2,2 (b) 2,1 (c) 1,2 (d) 1,1 7.5 PREPARATION OF HALOARENES 18. In the preparation of chlorobenzene from aniline, the most suitable reagent is NCERT Page-296 / N-166 (a) chlorine in the presence of ultraviolet light (b) chlorine in the presence of AlCl3 (c) nitrous acid followed by heating with Cu2Cl2 (d) HCl and Cu2Cl2 19. Aryl halides can not be prepared by the reaction of aryl alcohols with PCl3, PCl5 or SOCl2 because (a) phenols are highly stable compounds. NCERT Page N-164 (b) carbon-oxygen bond in phenols has a partial double bond character. (c) carbon-oxygen bond is highly polar (d) all of these 20. Which of the following is the best method for synthesis of 1-bromo-3-chlorobenzene? (a) NCERT Page-296 / N-166 (b) (c) (d) 7.6 PHYSICAL PROPERTIES 21. The decreasing order of boiling points of alkyl halides is NCERT Page-298 / N-168 (a) RF > RCl > RBr > RI (b) RBr > RCl > RI > RF (c) RI > RBr > RCl > RF (d) RCl > RF > RI > RBr