CBSE Class 12 Chemistry Haloalkanes and Haloarenes MCQs Set 05

Question. Halogenation of alkanes is
(a) a reductive process
(b) an oxidative process
(c) an isothermal process
(d) an endothermal process
Answer: b

Question. Which one is most reactive towards S_N1 reaction ?
(a) C₆H₅CH(C₆H₅ )Br
(b) C₆H₅CH(CH₃ )Br
(c) C₆H₅C(CH₃)(C₆H₅ )Br
(d) C₆H₅CH₂Br
Answer: c

Question. C – X bond is strongest in
(a) CH₃Cl
(b) CH₃Br
(c) CH₃F
(d) CH₃I
Answer: c

Question. When 2-bromobutane reacts with alcoholic KOH, the reaction is called
(a) halogenation
(b) chlorination
(c) hydrogenation
(d) dehydrohalogenation
Answer: d

Question. Tertiary alkyl halides are practically inert to substitution by S_N2 mechanism because of
(a) steric hindrance
(b) inductive effect
(c) instability
(d) insolubility
Answer: b

Question. Haloarenes are ortho and para directing due to
(a) Resonance in aryl halide
(b) – I effect of halogen atom
(c) + I effect of halogen atom
(d) Both (a) and (b)
Answer: d

Question. Chloroform is used as :
(a) Fire extinguisher
(b) Industrial solvent
(c) Refrigerant
(d) Insecticide
Answer: b

Question. The compound which contains all the four 1°, 2°, 3° and 4° carbon atoms is
(a) 2, 3-dimethyl pentane
(b) 3-chloro-2, 3-dimethylpentane
(c) 2, 3, 4-trimethylpentane
(d) 3, 3-dimethylpentane
Answer: b

Question. An organic compound A (C₄H₉Cl) on reaction with Na/diethyl ether gives a hydrocarbon which on monochlorination gives only one chloro derivative, then A is
(a) tert-butyl chloride
(b) sec-butyl chloride
(c) isobutyl chloride
(d) n-butyl chloride
Answer: a

Question. Racemic compound has
(a) equimolar mixture of enantiomers
(b) 1 : 1 mixture of enantiomer and diastereomer
(c) 1 : 1 mixture of diastereomers
(d) 1 : 2 mixture of enantiomers
Answer: a

 Question. Chlorobenzene is prepared commercially by
(a) Raschig process
(b) Wurtz Fittig reaction
(c) Friedel-Craft’s reaction
(d) Grignard reaction
Answer: a

Question. Gem-dibromide is
(a) CH₃CH(Br)CH₂(Br)
(b) CH₃CBr₂CH₃
(c) CH₂(Br)CH₂CH₂
(d) CH₂BrCH₂Br
Answer: b

Question. IUPAC name of (CH₃)₃CCl
(a) 3-Chlorobutane
(b) 2-Chloro-2-methylpropane
(c) t-butyl chloride
(d) n-butyl chloride
Answer: b

Question. Which of the following are the harmful effects of methylene chloride?
(a) Impaired hearing and vision
(b) Dizziness, nausea and tingling
(c) Skin burning
(d) All of these
Answer: d

Question. Which among MeX, RCH₂X, R₂CHX and R₃CX is most reactive towards S_N2 reaction?
(a) MeX
(b) RCH₂X
(c) R₂ C HX
(d) R₃CX
Answer: a

Question. Which of the following reactions is an example of nucleophilic substitution reaction?
(a) 2 RX + 2 Na → R – R + 2 NaX
(b) RX + H₂ → RH + HX
(c) RX + Mg → RMgX
(d) RX + KOH → ROH + KX
Answer: d

 Question. Which of the following will have the maximum dipole moment?
(a) CH₃F
(b) CH₃Cl
(c) CH₃Br
(d) CH₃I
Answer: b

Question. Isopropyl chloride undergoes hydrolysis by
(a) S_N1 mechanism
(b) S_N2 mechanism
(c) S_N1 and S_N2 mechanisms
(d) Neither S_N1 nor S_N2 mechanism
Answer: c

 Question. Which of the following is not used in Friedel-Crafts reaction?
(a) N–Phenyl acetanilide
(b) Bromobenzene
(c) Benzene
(d) Chlorobenzene
Answer: a

Question. If chloroform is left open in air in the presence of sunlight, it gives
(a) carbon tetrachloride
(b) carbonyl chloride
(c) mustard gas
(d) lewisite
Answer: b

Question. The order of reactivity of the given haloalkanes towards nucleophile is :
(a) RI > RBr > KCl
(b) RCl > RBr > RI
(c) RBr > RCl > RI
(d) RBr > RI > RCl
Answer: a

 Question. Full name of DDT is
(a) 1, 1, 1-trichloro-2, 2-bis(p-chlorophenyl) ethane
(b) 1, 1-dichloro-2, 2-diphenyl trimethylethane
(c) 1, 1-dichloro-2, 2-diphenyl trichloroethane
(d) None of these
Answer: a

Question. Silver acetate + Br₂ CS₂ →. The main product of this reaction is
(a) CH₃ – Br
(b) CH₃COI
(c) CH₃COOH
(d) None of these
Answer: a

Question. Methylene chloride can be used as
(a) paint remover
(b) propellant in aerosols
(c) solvent in manufacturing of drugs
(d) All of these
Answer: d

 Question. Uses of dichloromethane is
(a) paint remover
(b) solvent in drugs manufacturing
(c) metal cleansing and finishing solvent
(d) All of the above
Answer: d

Question. Freon (dichlorodifluoro methane) is used
(a) as local anaesthetic
(b) for dissolving impurities in metallurgical process
(c) in refrigerator
(d) in printing industry
Answer: c

Question. Ethylene dichloride can be prepared by adding HCl to
(a) Ethane
(b) Ethylene
(c) Acetylene
(d) Ethylene glycol
Answer: d

Question. A Grignard reagent may be made by reacting magnesium with
(a) Methyl amine
(b) Diethyl ether
(c) Ethyl iodide
(d) Ethyl alcohol
Answer: c

Question. Use of chlorofluorocarbons is not encouraged because
(a) They are harmful to the eyes of people that use it
(b) They damage the refrigerators and air conditioners
(c) They eat away the ozone in the atmosphere
(d) They destroy the oxygen layer
Answer: c

Question. Most reactive halide towards S_N1 reaction is
(a) n-Butyl chloride
(b) sec-Butyl chloride
(c) tert-Butyl chloride
(d) Allyl chloride
Answer: c

Question. Which of the following is used in fire extinguishers
(a) CH₄
(b) CHCl₃
(c) CH₂Cl₂
(d) CCl₄
Answer: d

Question. Reactivity order of halides for dehydrohalogenation is
(a) R – F > R – Cl > R – Br > R –I
(b) R –I > R – Br > R – Cl > R – F
(c) R –I > R – Cl > R – Br > R – F
(d) R – F > R –I > R – Br > R – Cl
Answer: b

Question. Mg reacts with RBr best in
(a) C₂H₅OC₂H₅
(b) C₆H₅OCH₃
(c) C₆H₅N(CH₃)₂
(d) Equally in all the three
Answer: a

Question. Chlorobenzene can be prepared by reacting aniline with :
(a) hydrochloric acid
(b) cuprous chloride
(c) chlorine in presence of anhydrous aluminium chloride
(d) nitrous acid followed by heating with cuprous chloride
Answer: d