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Free download in PDF Class 12 Chemistry Chapter 10 Haloalkanes and Haloarenes Multiple Choice Questions (MCQs) and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams like NEET, AIIMS, JIPMER etc. These short solved questions or quizzes are provided by Gkseries./p>
(1)
C-Cl bond of chlorobenzene in comparison to C-Cl bond in methyl chloride is
[A]
Longer and weaker
[B]
Shorter and weaker
[C]
Shorter and stronger
[D]
Longer and stronger
Answer: Shorter and stronger
(2)
A solution of (+) 2-chloro-2-phenylethane in toluene racemises slowly in the presence of a small amount of SbCl5, due to the formation of
[A]
carbanion
[B]
carbene
[C]
free radical
[D]
carbocation
(3)
Phosgene is commonly known as
[A]
thionyl chloride
[B]
carbonyl chloride
[C]
carbon dioxide and phosphine
[D]
phosphoryl chloride
Answer: carbonyl chloride
(4)
The reaction of tert butyl bromide with sodium methoxide produces mainly
[A]
isobutane
[B]
isobutylene
[C]
tert-butyl methyl ether
[D]
sodium tert butoxide
(5)
Which of the following undergoes nucleophilic substitution exclusively by SN1 mechanism?
[A]
Benzyl Chloride
[B]
Ethyl chloride
[C]
Chlorobenzene
[D]
Isopropyl chloride
(6)
The increasing order of nucleophilicity would be?
[A]
Cl– < Br– < I–
[B]
I– < Cl– < Br–
[C]
Br– < Cl– < F–
[D]
I– < Br– < Cl–
(7)
Which of the following is most reactive towards SN1 reaction?
[A]
C6H5C(CH3)C6H5Br
[B]
C8H5CH2Br
[C]
C6H5CH(C6H5)Br
[D]
C6H5CH(CH3)Br
(8)
CH3CH2CH2Br + NaCN → CH3CH2CH2CN + NaBr, will be fastest in
[A]
ethanol
[B]
methanol
[C]
N, N-dimethylformamide
[D]
Water
Answer: N, N-dimethylformamide
(9)
A Grignard reagent may be made by reacting magnesium with
[A]
Methyl amine
[B]
Diethyl ether
[C]
Ethyl iodide
[D]
Ethyl alcohol
(10)
Which of the following undergoes nucleophilic substitution exclusively by SN 1 mechanism?
[A]
Benzyl chloride
[B]
Ethyl chloride
[C]
Chlorobenzene
[D]
Isopropyl chloride
(11)
The increasing order of nucleophilicity would be
[A]
Cl– < Br– < I–
[B]
I– < Cl– < Br–
[C]
Br– < Cl– < F–
[D]
I– < Br– < Cl–
(12)
Which of the following is most reactive towards SN1 reaction?
[A]
C6H5C(CH3)C6H5Br
[B]
C6H5CH2Br
[C]
C6H5CH(C6H5)Br
[D]
C6H5CH(CH3)Br
(13)
CH3CH2CH2Br + NaCN → CH3CH2CH2CN + NaBr, will be fastest in
[A]
ethanol
[B]
methanol
[C]
N, N dimethyl formamide
[D]
Water
Answer: N, N dimethyl formamide
(14)
A dihalogen derivative ‘X’ of a hydrocarbon with three carbon atoms react with ale. KOH and produces hydrocarbon which forms red ppt. with ammonical Cu2Cl2. ‘X’ gives an aldehyde on reaction with aq. KOH. The compound ‘X’ is
[A]
1, 3-Dichloropropane
[B]
1, 2-Dichloropropane
[C]
2, 2-Dichloropropane
[D]
1, 1-Dichloropropane
Answer: 1, 1-Dichloropropane
(15)
The synthesis of alkyl fluoride is best accomplished by
[A]
Finkelstein reaction
[B]
Swartz reaction
[C]
Free radical fluorination
[D]
Sandmeyers reaction
(16)
How many chiral compounds are possible on monochlorination of 2-methyl butane?
(17)
Which of the following alkyl halides will undergo SN1 reaction most readily?
[A]
(CH3)3 C—F
[B]
(CH3)3 C—Cl
[C]
(CH3)3 C—Br
[D]
(CH3)3 C—I
(18)
Which of the following compounds will give racemic mixture on nucleophilic substitution by OH” ion?
1-Bromoethane, 1-Bromopropane, 1-Bromobutane, Bromobenzene
[A]
Bromobenzene < 1-Bromobutane < 1-Bromopropane < 1-Bromoethane
[B]
Bromobenzene < 1-Bromoethane < 1-Bromopropane < 1-Bromobutane
[C]
1-Bromopropane < 1-Bromobutane < 1-Bromoethane < Bromobenzene
[D]
1-Bromoethane < 1-Bromopropane < 1-Bromobutane < Bromobenzene
Answer: Pentane – 1, 2, 3, 4 – tetraol
(19)
SN1 reaction of alkyl halides lead to
[A]
Retention of configuration
[B]
Racemisation
[C]
Inversion of configuration
[D]
None of these
(20)
p-djchlorobenzene has higher melting point than its o- and m- isomers because
[A]
p-dichlorobenzene is more polar than o- and m- isomer
[B]
p-isomer has a symmetrical crystalline structure
[C]
boiling point of p-isomer is more than o- and m-isomer
[D]
All of these are correct reasons
Answer: p-isomer has a symmetrical crystalline structure
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