CBSE Class 12 Chemistry Haloalkanes and Haloarenes MCQs Set 03

Question. Among the following which one has weakest carbon-halogen bond?
(a) Benzyl bromide
(b) Bromobenzene
(c) Vinyl bromide
(d) Benzyl chloride

Answer : A

Question. Which one of the following chlorohydrocarbons readily undergoes solvolysis ?

Answer : D

Question. The compound formed on heating chlorobenzene with chloral in the presence of concentrated sulphuric acid is
(a) gammexane
(b) DDT
(c) freon
(d) hexachloroethane

Answer : B

Question. X →_HNO3^AgNO3 yellow or white ppt Which of the following cannot be X? 

Answer : A

Question. Fluorobenzene (C₆H₅F) can be synthesised in the laboratory
(a) by heating phenol with HF and KF 
(b) from aniline by diazotisation followed by heating the diazonium salt with HBF₄
(c) by direct tluorination of benzene with F₂ gas
(d) by reacting bromobenzene with NaF solution

Answer : B

Question. A compound of molecular formula C₇H₁₆ shows optical isomerism, compound will be
(a) 2,3-dimethylpentane
(b) 2,2-dimethylbutane
(c) 2-methylhexane
(d) none of these.

Answer : A

Question. Which of the following compounds is not chiral?
(a) CH₃CHDCH₂Cl
(b) CH₃CH₂CHDCl
(c) DCH₂CH₂CH₂Cl
(d) CH₃CHClCH₂D

Answer : C

Question. Replacement of Cl of chlorobenzene to give phenol requires drastic conditions. But chlorine of 2,4-dinitrochlorobenzene is readily replaced because
(a) NO₂ donates e– at meta position
(b) NO₂ withdraws e– from ortho/para positions
(c) NO₂ makes ring electron rich at ortho and para
(d) NO₂ withdraws e– from meta position.

Answer : B

Question. The alkyl halide is converted into an alcohol by
(a) elimination
(b) dehydrohalogenation
(c) addition
(d) substitution.

Answer : D

Question. Reaction of t-butyl bromide with sodium methoxide produces
(a) sodium t-butoxide
(b) t-butyl methyl ether
(c) isobutane
(d) isobutylene.

Answer : D

Question. Consider the reaction, CH₃CH₂CH₂Br + NaCN →CH₃CH₂CH₂CN + NaBr
This reaction will be the fastest in
(a) ethanol
(b) methanol
(c) N, N -dimethylformamide (DMF)
(d) water.

Answer : C

Question. Two possible stereo-structures of CH₃CHOHCOOH,which are optically active, are called
(a) atropisomers
(b) enantiomers
(c) mesomers
(d) diastereomers.

Answer : B

Question. In an SN₁ reaction on chiral centres, there is
(a) inversion more than retention leading to partial racemisation
(b) 100% retention
(c) 100% inversion
(d) 100% racemisation.

Answer : A

Question. Which of the following acids does not exhibit optical isomerism?
(a) Maleic acid
(b) a-Amino acids
(c) Lactic acid
(d) Tartaric acid

Answer : A

Question. Which one is most reactive towards SN₁ reaction?
(a) C₆H₅CH(C₆H₅)Br
(b) C₆H₅CH(CH₃)Br
(c) C₆H₅C(CH₃)(C6H₅)Br
(d) C₆H₅CH₂Br

Answer : C

Question. Chlorobenzene gives aniline with 
(a) NH₃/Cu₂O
(b) NH₃/H₂SO₄
(c) NaNH₂
(d) None of these

Answer : A

Question. Which of the following is least reactive in a nucleophilic substitution reaction?
(a) (CH₃)₃C – Cl
(b) CH₂ = CHCl
(c) CH₃CH₂Cl
(d) CH₂ = CHCH₂Cl

Answer : B

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. obtained by chlorination of n-butane will be
(a) meso form
(b) racemic mixture
(c) d-form
(d) l-form.

Answer : B

Question. An organic compound A(C₄H₉C_l) on reaction with Na/diethyl ether gives a hydrocarbon which on monochlorination gives only one chloro derivative then, A is
(a) t-butyl chloride
(b) s-butyl chloride
(c) iso-butyl chloride
(d) n-butyl chloride.

Answer : A