VBQ Haloalkanes and Haloarenes Class 12 Chemistry

VBQs Haloalkanes and Haloarenes Class 12 Chemistry with Haloalkanes and Haloarenes has been provided below for standard students. We have provided chapter wise VBQ for Class 12 Chemistry with Haloalkanes and Haloarenes. The following Haloalkanes and Haloarenes Class 12 Chemistry value based questions with answers will come in your exams. Students should understand the concepts and learn the solved cased based VBQs provided below. This will help you to get better marks in class 12 examinations.

Haloalkanes and Haloarenes VBQs Class 12 Chemistry

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

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

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

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

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

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

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

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

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

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

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

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

Question.

(a) substitution
(b) elimination
(c) addition
(d) rearrangement reaction

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

Question. The reaction conditions leading to the best yields of C₂H₅Cl are :

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

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

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

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

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

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

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

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

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

Question. Which of the following is an example of S_N2 reaction?

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

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

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

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

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

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

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

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

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)

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

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

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

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

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

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

Question. Chloropicrin is obtained by the reaction of
(a) steam on carbon tetrachloride
(b) nitric acid on chlorobenzene
(c) chlorine on picric acid
(d) nitric acid on chloroform

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

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

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

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

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

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

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

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

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

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

Question. Trichloroacetaldehyde, CCl₃CHO reacts with chlorobenzene in presence of sulphuric acid and produces:

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

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

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

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)

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

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

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

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

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

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

Question.

The above structural formula refers to
(a) BHC
(b) DNA
(c) DDT
(d) RNA

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

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

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

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

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

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