JEE Chemistry Haloalkanes and Haloarenes MCQs Set A

Question: Which of the following is a primary halide?

• a) Neohexyl chloride
• b) Secondary butyl iodide
• c) Isopropyl iodide
• d) Tertiary butyl bromide

Answer: Neohexyl chloride

Question: When two halogen atoms are attached to same carbon atom then it is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Gem-dibromide is

• a) CH₃CBr₂CH₃
• b) CH₂BrCH₂Br
• c) CH₂(Br)CH₂CH₂
• d) None of these

Answer: CH₃CBr₂CH₃

Question: How many structural isomers are possible for a compound with molecular formula C₃H₇Cl ?

• a) 2
• b) 7
• c) 5
• d) 9

Answer: 2

Question: The compound which contains all the four 1°, 2°, 3° and 4° carbon atoms is

• a) 3-chloro-2, 3-dimethylpentane
• b) 2, 3-dimethyl pentane
• c) 2, 3, 4-trimethylpentane
• d) 3, 3-dimethylpentane

Answer: 3-chloro-2, 3-dimethylpentane

Question: IUPAC name of (CH₃)₃CCl

• a) 2-Chloro-2-methylpropane
• b) 3-Chlorobutane
• c) n-butyl chloride
• d) t-butyl chloride

Answer: 2-Chloro-2-methylpropane

Question:

• a) 2-bromo-1-chloro butene
• b) 1-chloro-2-bromo butene
• c) 3-chloro-2-bromo butene
• d) None of the above

Answer: 2-bromo-1-chloro butene

Question:

• a) 3-chloro-1-propene
• b) 1-chloro-3-propene
• c) Allyl chloride
• d) Vinyl chloride

Answer: 3-chloro-1-propene

Question:  Which of the following halide is 2°

• a) Isopropyl chloride
• b) n-propyl chloride
• c) n-butyl chloride
• d) Isobutyl chloride

Answer: Isopropyl chloride

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: 1, 2, 3, 4, 5, 6 - hexachlorocyclohexane

Question: Phosgene is a common name for

• a) carbonyl chloride
• b) carbon dioxide and phosphine
• c) thionyl chloride
• d) phosphoryl chloride

Answer: carbonyl chloride

Question: C – X bond is strongest in

• a) CH₃F
• b) CH₃Cl
• c) CH₃Br
• d) CH₃I

Answer: CH₃F

Question: Which of the following will have the maximum dipole moment?

• a) CH₃Cl
• b) CH₃I
• c) CH₃F
• d) CH₃Br

Answer: CH₃Cl

Question:  The decreasing order of boiling points of alkyl halides is

• a) RI > RBr > RCl > RF
• b) RF > RCl > RBr > RI
• c) RBr > RCl > RI > RF
• d) RCl > RF > RI > RBr

Answer: RI > RBr > RCl > RF

Question:

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

Answer: substitution

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

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Halogenation of alkanes is

• a) an oxidative process
• b) an endothermal process
• c) a reductive process
• d) an isothermal process

Answer: an oxidative process

Question: Ethylene dichloride can be prepared by adding HCl to

• a) Ethylene glycol
• b) Ethylene
• c) Ethane
• d) Acetylene

Answer: Ethylene glycol

Question: In which of the following conversions, phosphorus pentachloride is used as the reagent?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The best method for the conversion of an alcohol into an alkyl chloride is by treating the alcohol with

• a) SOCl₂ in presence of pyridine
• b) None of these
• c) dry HCl in the presence of anhydrous ZnCl₂
• d) PCl₅

Answer: SOCl₂ in presence of pyridine

More Questions..........................

Question: Which of the following is liquid at room temperature (b.p. is shown against it) ?

• a) CH₃I 42ºC
• b) CH₃Br 3ºC
• c) CH₃F –78ºC
• d) None of these

Answer: CH₃I 42ºC

Question: The catalyst used in the preparation of an alkyl chloride by the action of dry HCl on an alcohol is

• a) anhydrous ZnCl₂
• b) anhydrous AlCl₃
• c) FeCl₃
• d) Cu

Answer:  anhydrous ZnCl₂

Question: Chlorobenzene is prepared commercially by

• a) Raschig process
• b) Wurtz Fittig reaction
• c) Friedel-Craft’s reaction
• d) Grignard reaction

Answer: Raschig process

Question: In the preparation of chlorobenzene from aniline, the most suitable reagent is

• a) Nitrous acid followed by heating with Cu₂Cl₂
• b) Chlorine in the presence of AlCl₃
• c) Chlorine in the presence of ultraviolet light
• d) None of these

Answer: Nitrous acid followed by heating with Cu₂Cl₂

Question: Which of the following possesses highest melting point?

• a) p-dichlorobenzene
• b) m-dichlorobenzene
• c) Chlorobenzene
• d) o-dichlorobenzene

Answer: p-dichlorobenzene

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

• a) Sodium iodide is soluble in methanol, while NaCl and NaBr are insoluble in methanol
• b) Sodium iodide is insoluble in methanol, while NaCl and NaBr are soluble
• c) The three halogens differ considerably in their electronegativity
• d) Sodium iodide is soluble in methanol, while sodium chloride is insoluble in methanol

Answer: Sodium iodide is soluble in methanol, while NaCl and NaBr are insoluble in methanol

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:  Which of the following reactions is an example of nucleophilic substitution reaction

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A Grignard reagent may be made by reacting magnesium with

• a) Ethyl iodide
• b) Methyl amine
• c) Diethyl ether
• d) Ethyl alcohol

Answer: Ethyl iodide

Question: Which one of the following halogen compounds is difficult to be hydrolysed by S_N1 mechanism?

• a) Chlorobenzene
• b) Isopropyl chloride
• c) Tertiary butyl chloride
• d) Benzyl chloride

Answer: Chlorobenzene

Question: The order of reactivity of the given haloalkanes towards nucleophile is

• a) RI > RBr > KCl
• b) RBr > RCl > RI
• c) RCl > RBr > RI
• d) RBr > RI > RCl

Answer: RI > RBr > KCl

Question: Most reactive halide towards S_N1 reaction is

• a)

  

• b) n-Butyl chloride
• c) sec-Butyl chloride
• d) Allyl chloride

Answer: 

Question: In S_N1 reaction, the recemization takes place. It is due to

• a) Both
• b) inversion of configuration
• c) retention of configuration
• d) None of these

Answer: Both

Question: The order of reactivities of the following alkyl halides for a S_N2 reaction is

• a) RI > RBr > RCl > RF
• b) RF > RBr > RCl > RI
• c) RF > RCl > RBr > RI
• d) RCl > RBr > RF > RI

Answer: RI > RBr > RCl > RF

Question:  Which of the following is an example of S_N2 reaction

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: S_N2 mechanism proceeds through intervention of

• a) transition state
• b) carbanion
• c) carbonium ion
• d) free radical

Answer: transition state

Question: Which among MeX, RCH₂X, R₂CHX and R₃CX is most reactive towards S_N2 reaction?

• a) MeX
• b) RCH₂X
• c) R₃CX
• d) R₂CHX

Answer: MeX

Question: Isopropyl chloride undergoes hydrolysis by

• a) S_N1 and S_N2 mechanisms
• b) S_N2 mechanism
• c) S_N1 mechanism
• d) None of these

Answer: S_N1 and S_N2 mechanisms

Question: Tertiary alkyl halides are practically inert to substitution by S_N2 mechanism because of

• a) inductive effect
• b) insolubility
• c) instability
• d) steric hindrance

Answer: inductive effect

Question: Which of the following is the correct order of decreasing S_N2 reactivity?

(X is a halogen)

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) S_N2
• b) S_E2
• c) S_N1
• d) S_N0

Answer: S_N2

Question: Which of the following is an optically active compound ?

• a) 2-Chlorobutane
• b) 1-Butanol
• c) 1-Propanol
• d) 4-Hydroxyheptane

Answer: 2-Chlorobutane

Question: An important chemical method to resolve a racemic mixture makes use of the formation of

• a) diasteromers
• b) a meso compound
• c) enantiomers
• d) racemates

Answer: diasteromers

Question:

• a) Resolution
• b) Revolution
• c) Dehydration
• d) Dehydrohalogenation

Answer: Resolution

Question: Which of the following pairs of compounds are enantiomers?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Which of the following will have a mesoisomer also

• a) 2, 3-Dichlorobutane
• b) 2-Chlorobutane
• c) 2-Hydroxypropanoic acid
• d) 2, 3- Dichloropentane

Answer: 2, 3-Dichlorobutane

Question: Which of the following compounds is optically active

• a) CH₃CHClCOOH
• b) (CH₃)₂CHOH
• c) (CH₃)₃CCl
• d) None of these

Answer: CH₃CHClCOOH

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:  equimolar mixture of enantiomers

Question: An organic molecule necessarily shows optical activity if it

• a) is non-superimposable on its mirror image
• b) is superimposable on its mirror image
• c) is non-polar
• d) contains asymmetric carbon atoms

Answer: is non-superimposable on its mirror image

Question: Optically active isomers but not mirror images are called

• a) diastereomers
• b) mesomers
• c) enantiomers
• d) tautomers

Answer:  diastereomers

Question: Which of the following alkyl halides is used as a methylating agent?

• a) CH₃I
• b) C₆H₅Cl
• c) C₂H₅Cl
• d) None of these

Answer: CH₃I

Question: Mg reacts with RBr best in

• a)

  

• b)

  

• c)

  

• d) Equally in all the three

Answer:

Question: 2-Bromopentane is heated with potassium ethoxide in ethanol. The major product obtained is

• a) trans-2-pentene
• b) 2-ethoxypentane
• c) pentene-1
• d) cis-pentene-2

Answer: trans-2-pentene

Question: An alkyl halide reacts with metallic sodium in dry ether. The reaction is known as

• a) Wurtz reaction
• b) Frankland’s reaction
• c) Sandmeyer’s reaction
• d) Kolbe’s reaction

Answer: Wurtz reaction

Question: When 2-bromobutane reacts with alcoholic KOH, the reaction is called

• a) dehydrohalogenation
• b) chlorination
• c) halogenation
• d) hydrogenation

Answer: dehydrohalogenation

Question: An alkyl halide by formation of its Grignard reagent and heating with water yields propane. What is the original alkyl halide ?

• a) Propyl bromide
• b) Ethyl iodide
• c) Methyl iodide
• d) Ethyl bromide

Answer:  Propyl bromide

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) isobutyl chloride
• c) sec-butyl chloride
• d) n-butyl chloride

Answer: tert-butyl chloride

Question: Elimination of bromine from 2-bromobutane results in the formation of –

• a) predominantly 2-butene
• b) predominantly 1-butene
• c) predominantly 2-butyne
• d) equimolar mixture of 1 and 2-butene

Answer: predominantly 2-butene

Question: Isobutyl magnesium bromide with dry ether and ethyl alcohol gives

• a) 

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Reactivity order of halides for dehydrohalogenation is

• a) R –I > R – Br > R – Cl > R – F
• b) R – F > R – Cl > R – Br > R –I
• c) R –I > R – Cl > R – Br > R – F
• d) R – F > R –I > R – Br > R – Cl

Answer: R –I > R – Br > R – Cl > R – F

Question:

• a) 1 < 2 < 3
• b) 3 < 1 < 2
• c) 2 < 1 < 3
• d) 2 < 3 < 1

Answer: 1 < 2 < 3

Question: Which of following can be used as solvent for grignard reagent ?

• a) C₂H₅OC₂H₅
• b) C₂H₅OH
• c) H₂O
• d) None of these

Answer: C₂H₅OC₂H₅

Question: Benzene reacts with CH₃Cl in the presence of anhydrous AlCl₃ to form

• a) toluene
• b) benzylchloride
• c) chlorobenzene
• d) xylene

Answer: toluene

Question: Chlorobenzene reacts with Mg in dry ether to give a compound (A) which further reacts with ethanol to yield

• a) Benzene
• b) Phenyl ether
• c) Phenol
• d) Ethylbenzene

Answer: Benzene

Question: Benzene reacts with n-propyl chloride in the presence of anhydrous AlCl₃ to give

• a) Isopropylbenzene
• b) No reaction
• c) n-Propylbenzene
• d) 3 – Propyl – 1 – chlorobenzene

Answer: Isopropylbenzene

Question: Which of the following is the example of Friedal Craft reaction?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: On sulphonation of C₆H₅Cl

• a) ortho and para chlorobenzene sulphonic acids are formed
• b) orthochlorobenzene sulphonic acid is formed
• c) metachlorobenzene sulphonic acid is formed
• d) benzene sulphonic acid is formed

Answer: ortho and para chlorobenzene sulphonic acids are formed

Question: C – Cl bond of chlorobenzene in comparison to C – Cl bon in methyl chloride is

• a) Shorter and stronger
• b) Longer and weaker
• c) Shorter and weaker
• d) Longer and stronger

Answer: Shorter and stronger

Question:  Which of the following is not used in Friedel-Crafts reaction?

• a) N–Phenyl acetanilide
• b) Benzene
• c) Bromobenzene
• d) Chlorobenzene

Answer: N–Phenyl acetanilide

Question: Which one of the following is most reactive towards nucleophilic substitution reaction?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question:  Which one is most reactive towards S_N1reaction

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Chlorobenzene can be prepared by reacting aniline with

• a) nitrous acid followed by heating with cuprous chloride
• b) chlorine in presence of anhydrous aluminium chloride
• c) cuprous chloride
• d) hydrochloric acid

Answer: nitrous acid followed by heating with cuprous chloride

Question: Aryl halides can not be prepared by the reaction of aryl alcohols with PCl₃, PCl₅ or SOCl₂ because

• a) carbon-oxygen bond in phenols has a partial double bond character
• b) carbon-oxygen bond is highly polar
• c) all of these
• d) phenols are highly stable compounds

Answer: carbon-oxygen bond in phenols has a partial double bond character

Question: Haloarenes are ortho and para directing due to

• a) Both
• b) + I effect of halogen atom
• c) – I effect of halogen atom
• d) Resonance in aryl halide

Answer: Both

Question: Chloropicrin is obtained by the reaction of

• a) nitric acid on chloroform
• b) chlorine on picric acid
• c) nitric acid on chlorobenzene
• d) steam on carbon tetrachloride

Answer: nitric acid on chloroform

Question: Which of these can be used as moth repellant

• a) Hexachloroethane
• b) Benzene hexachloride
• c) Benzal chloride
• d) Tetrachloroethane

Answer: Hexachloroethane

Question:

• a) they deplete ozone layer
• b) None of the these
• c) these are difficult to synthesise
• d) these are fluorocarbons

Answer: they deplete ozone layer

Question: Freon (dichlorodifluoro methane) is used

• a) in refrigerator
• b) for dissolving impurities in metallurgical process
• c) as local anaesthetic
• d) in printing industry

Answer: in refrigerator

Question: Use of chlorofluorocarbons is not encouraged because

• a) They eat away the ozone in the atmosphere
• b) They destroy the oxygen layer
• c) They damage the refrigerators and air conditioners
• d) They are harmful to the eyes of people that use it

Answer: They eat away the ozone in the atmosphere