CBSE Class 12 Chemistry Haloalkanes and Haloarenes MCQs Set 06

Question. When two halogen atoms are attached to same carbon atom then it is :
(a) vic-dihalide
(b) gem-dihalide
(c) α, ω -halide
(d) α, β -halide
Answer: b

Question. How many structural isomers are possible for a compound with molecular formula C₃H₇Cl ?
(a) 2
(b) 5
(c) 7
(d) 9
Answer: a

Question. Freon(s) is/are :
(a) CClF₃
(b) CFCl₃
(c) CCl₂F₂
(d) All of these
Answer: d

Question. Haloforms are trihalogen derivatives of
(a) Ethane
(b) Methane
(c) Propane
(d) Benzene
Answer: b

Question. In which of the following conversions, phosphorus pentachloride is used as the reagent?
(a) H₂C = CH₂ → CH₃CH₂Cl
(b) CH₃CH₂OH → CH₃CH₂Cl
(c) H₃C- O – CH₃ → CH₃Cl
(d) CH ≡ CH → CH₂ = CHCl
Answer: b

Question. Which one of the following halogen compounds is difficult to be hydrolysed by S_N1 mechanism?
(a) Tertiary butyl chloride
(b) Isopropyl chloride
(c) Benzyl chloride
(d) Chlorobenzene
Answer: d

Question. Which of these can be used as moth repellant
(a) Benzene hexachloride
(b) Benzal chloride
(c) Hexachloroethane
(d) Tetrachloroethane
Answer: b

Question. AgNO₃ does not give precipitate with CHCl₃ because
(a) CHCl₃ does not ionise in water
(b) CHCl₃ does not react with AgNO₃
(c) CHCl₃ is chemically inert
(d) None of these
Answer: a

Question. Which of the following halide is 2° ?
(a) Isopropyl chloride
(b) Isobutyl chloride
(c) n-propyl chloride
(d) n-butyl chloride
Answer: a

Question. Chloroform on treatment with conc. HNO₃ gives
(a) Chloropicrin
(b) Nitromethane
(c) Picric acid
(d) Acetylene
Answer: a

Question. Phosgene is a common name for
(a) phosphoryl chloride
(b) thionyl chloride
(c) carbon dioxide and phosphine
(d) carbonyl chloride
Answer: d

Question. Conant Finkelstein reaction for the preparation of alkyl iodide is based upon the fact that
(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
Answer: b

Question. Benzene hexachloride is
(a) 1, 2, 3, 4, 5, 6 – hexachlorocyclohexane
(b) 1, 1, 1, 6, 6, 6 – hexachlorocyclohexane
(c) 1, 6 – phenyl – 1, 6 – chlorohexane
(d) 1, 1 – phenyl – 6, 6 -chlorohexane
Answer: a

Question. The IUPAC name of CH₂ = CH — CH₂Cl is
(a) Allyl chloride
(b) 1-chloro-3-propene
(c) Vinyl chloride
(d) 3-chloro-1-propene
Answer: d

Question. Which of the following possesses highest melting point?
(a) Chlorobenzene
(b) m-dichlorobenzene
(c) o-dichlorobenzene
(d) p-dichlorobenzene
Answer: d

Question. The best method for the conversion of an alcohol into an alkyl chloride is by treating the alcohol with
(a) PCl₅
(b) dry HCl in the presence of anhydrous ZnCl₂
(c) SOCl₂ in presence of pyridine
(d) None of these
Answer: c

Question. In S_N1 reaction, the recemization takes place. It is due to
(a) inversion of configuration
(b) retention of configuration
(c) conversion of configuration
(d) Both (a) and (b)
Answer: d

Question. S_N2 mechanism proceeds through intervention of
(a) carbonium ion
(b) transition state
(c) free radical
(d) carbanion
Answer: b

Question. Which of the following compounds is optically active ?
(a) CH₃CHClCOOH
(b) CH₃CH₂CH₂CH₃
(c) (CH₃)₂CHOH
(d) (CH₃)₃CCl
Answer: a

Question. CF_xCl_y [where x + y = 4]. These compounds are not used because
(a) these are fluorocarbons
(b) these are difficult to synthesise
(c) they deplete ozone layer
(d) None of the these
Answer: b

 Question. Arrange the following alcohols in increasing order of their reactivity towards the reaction with HCl.
(CH₃)₂CH-OH (1), (CH₃)₃C-OH (2), (C₆H₅)₃C-OH (3)
(a) 1 < 2 < 3
(b) 2 < 1 < 3
(c) 3 < 1 < 2
(d) 2 < 3 < 1
Answer: a

 Question. Which of the following is a primary halide?
(a) Isopropyl iodide
(b) Secondary butyl iodide
(c) Tertiary butyl bromide
(d) Neohexyl chloride
Answer: d

Question. The catalyst used in the preparation of an alkyl chloride by the action of dry HCl on an alcohol is
(a) anhydrous AlCl₃
(b) FeCl₃
(c) anhydrous ZnCl₂
(d) Cu
Answer: c

Question. IUPAC name of
CH₃CH₂C(Br) = CH—Cl is
(a) 2-bromo-1-chloro butene
(b) 1-chloro-2-bromo butene
(c) 3-chloro-2-bromo butene
(d) None of the above
Answer: a

Question. In the preparation of chlorobenzene from aniline, the most suitable reagent is
(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
Answer: c

Question. The order of reactivities of the following alkyl halides for a S_N2 reaction is
(a) RF > RCl > RBr > RI
(b) RF > RBr > RCl > RI
(c) RCl > RBr > RF > RI
(d) RI > RBr > RCl > RF
Answer: d

Question. When chloroform is exposed to light and air, it forms
(a) chlorine gas
(b) methyl chloride
(c) phosgene gas
(d) carbon tetrachloride
Answer: c

Question. The decreasing order of boiling points of alkyl halides is
(a) RF > RCl > RBr > RI
(b) RBr > RCl > RI > RF
(c) RI > RBr > RCl > RF
(d) RCl > RF > RI > RBr
Answer: c

 Question. Which of the following is liquid at room temperature (b.p. is shown against it) ?
(a) CH₃I 42ºC
(b) CH₃Br 3ºC
(c) C₂H₅ Cl 12ºC
(d) CH₃F –78ºC
Answer: a