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CBSE Questions for Class 12 Engineering Chemistry Haloalkanes And Haloarenes Quiz 6 - MCQExams.com

Ethyl chloride is converted to butane by :
  • Kolbes synthesis
  • Williamson's synthesis
  • Wurtz reaction
  • Gattermann reaction
Chloroethane is reacted with alcoholic potassium hydroxide. The product formed is:
  • C2H6O
  • C2H6
  • C2H4
  • C2H4O
Reaction of ethyl chloride with sodium leads to (in the presence of dry ether):
  • ethane
  • propane
  • n-butane
  • n-pentane
1-Chlorobutane on reaction with alcoholic potash gives:
  • 1-butene
  • 1-butanol
  • 2-butene
  • 2-butanol
Which of the following is not true for SN1 reactions ?
  • These occur through a single step.
  • These are favoured by polar solvents.
  • 3o alkyl halides generally react through this mechanism.
  • Concentration of nucleophile does not affect the rate of such reactions.
C_6H_5-\!\!\!\!\!\underset{H}{\underset{|}{\overset{\,\,\,\,\,\,CH_3}{\overset{|}{C}}}}\!\!\!\!\!-Br+H_2O \to HO -\!\!\!\!\!\underset{H}{\underset{|}{\overset{\,\,\,\,\,\,CH_3}{\overset{|}{C}}}}\!\!\!\!\! -C_6H_5+HBr

The above reaction result in 98% racemization, the reaction mainly follows:
  • S_{N}1 mechanism
  • S_{N}2 mechanism
  • E^{1} mechanism
  • E^{2} mechanism
Reaction of Chlorobenzene with CH_3Cl in presence of AlCl_{3} gives:
  • Toulene
  • m-chloro toulene
  • Only o-chloro toulene
  • Mixture of o- and p-chlorotoulene
The correct match is :
  List-I  List-II
 A C_2H_5Cl 1 Williamson synthesis
 B R-X+Mg+dry ether 2 Wurtz reaction
 C C_2H_5Cl+C_2H_5ONa 3 Anaesthetic
 D Na+dry ether  4 Antiseptic
   5 Grignard reagent
  • A-3, B-5, C-1, D-2
  • A-5, B-3, C-1, D-2
  • A-3, B-4, C-1, D-2
  • A-3, B-5, C-1, D-4
The IUPAC name is:  H-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{Cl}{\overset{|}{C}}}}-Cl
  • 1,2 - dichoroethane
  • 2,2 - dichloroethane
  • 1,1 - Dichloroethane
  • dichloroethane
Which of the following statement is not correct?
  • Chlorobenzene is more reactive than benzene towards electrophilic substitution
  • C- Cl bond in chlorobenzene is less polar than CH Cl_{3}
  • Chlorobenzene is less reactive than CH Cl_{3}
  • In chlorobenzene further substitution takes place at ortho and para positions
Which of the following molecules is expected to rotate the plane of plane-polarised light?
Which of these is o, p-directing and deactivating group?
  • -F
  • -Cl
  • -Br
  • All of these
The compound X is:
15398.png
  • o-methylchlorobenzene
  • p-methylchlorobenzene
  • m-methylchlorobenzene
  • both A & B
The reaction of toluene with Cl_{2} in presence of Fe, the product(s) formed is/are:
  • o- and p-chlorotoluene
  • benzyl chloride
  • m-chlorotoluene
  • only p-chlorotoluene
If C_{4}H_{9}Cl with Na/ether gives 2,5-dimethylhexane, then the compound, C_{4}H_{9}Cl is:
  • n-butylchloride
  • sec-butylchloride
  • iso-butylchloride
  • tert-butylchloride
In the following pair of compounds, which compound is more nucleophilic in a polar-protic solvent? 
  
        { CH }_{ 3 }Cl or { CH }_{ 3 }OH
  • { CH }_{ 3 }Cl
  • { CH }_{ 3 }OH
  • { CH }_{ 3 }Cl = { CH }_{ 3 }OH
  • None of these

For the given pair of {{ S }_{ N }}1 reactions, the ______ reaction is faster.
141167.png
  • first
  • second
  • both progress at the same rate
  • cannot be determined
Which of the following relation is correct for recativity?

{ CH }_{ 3 }COO^{ - } or { CH }_{ 3 }{ CH }_{ 2 }S^{ - } with { CH }_{ 3 }I in ethanol.
  • { CH }_{ 3 }{ CH }_{ 2 }S^{ - } > { CH }_{ 3 }COO^{ - }
  • { CH }_{ 3 }{ CH }_{ 2 }S^{ - } < { CH }_{ 3 }COO^{ - }
  • { CH }_{ 3 }{ CH }_{ 2 }S^{ - } = { CH }_{ 3 }COO^{ - }
  • None of these
Which of the given pair of { S }_{ N }1 reaction would you expect to proceed faster? Explain your answer.

141353.png
  • {3}^{o}-alcohol > {2}^{o}-alcohol
  • {3}^{o}-alcohol < {2}^{o}-alcohol
  • {3}^{o}-alcohol = {2}^{o}-alcohol
  • None of these
Which of the following chlorides is highly reactive in {{ S }_{ N }}1 reaction, even solvolysed in cold water?
  • None of the above

Statement: In the above reaction,  first compound in the product side is the major product.

State whether the given statement is true or false

141360_68482d53f4b249fe815fef48ff8e200f.png
  • True
  • False
Which of the following statements/reactions are correct?
  • S_N2/E2 ratio is higher with RS^{\circleddash} than for those with RO^{\circleddash}
  • S_N2/E2 ratio is higher for 1^o RX and least for 3^oRX
  • Me_3C-Br+KCN\longrightarrow Me_3C-CN
  • None of the above
The alkyl halides required to prepare (CH_3)_2CH-CH_2-CH_2-CH_3 by Wurtz reaction are:
\underset { Specific\quad rotaion=+{ 50 }^{ o } }{ Ph-CH(OH){ CH }_{ 3 } } \xrightarrow [  ]{ SO{ Cl }_{ 2 } } \quad \underset { |\\ Cl }{ PhCl } -{ CH }_{ 3 }
Which of the following mechanisms does the reaction proceed?
  • {S_N}i
  • {S_N}^{2}
  • {S_N}^{1}
  • E_2
Assertion: E1cB reaction is favoured by stabilisation of carbanion and poor leaving group
Reason: The reaction is kinetically of the second-order and unimolecular
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Assertion is incorrect but Reason is correct
  • Both Assertion and Reason are incorrect
Assertion: 1^o allylic halides are more reactive than 1^oRX in S_N1 reaction
Reason: Allylic carbocation intermediate is stabilised by resonance
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Assertion is incorrect but Reason is correct
  • Both Assertion and Reason are incorrect
Which of the following aromatic compound is least reactive towards electrophilic substitutions?
The first steps of {SN}^{1} and {SN}^{2} reactions are, respectively:
  • Both exothermic
  • Both endothermic
  • Endothermic and exothermic
  • Exothermic and endothermic
Which one of the following compounds gives {S_N}{1}, {S_N}{2} and {S_N}{2'} mechanisms?
Nitration of xylene gives only one mono-nitro derivative. Which xylene is it?
  • ortho
  • meta
  • para
  • Both o and p
During S_N1 reactions, the leaving group leaves the molecule before the incoming group is attached to the molecule
  • True
  • False
By which mechanism does the above reaction proceed?
253048_b1d38e25e9904a6a8c93a632b9e5d834.png
  • E_1
  • E_2
  • E_1cb
  • \gamma-Elimination
Which of the following represents Westrosol?
  • CH{Cl}_{3}
  • {CH}_{2}{Cl}_{2}
  • CH{Cl}_{2}{CH}_{2}Cl
  • C{Cl}_{2}=CHCl
The chemical reaction:
{ \left( { CH }_{ 3 } \right)  }_{ 3 } CBr \xrightarrow [ { -H }_{ 2 }O,-KBr ]{ KOH(alc.) }  { \left( { CH }_{ 3 } \right)  }_{ 2 }C={CH}_{2} is an example of:
  • nucleophilic substitution
  • electrophilic substitution
  • free radical substitution
  • \beta-elimination
{C}_{3}{H}_{7}Cl \xrightarrow [  ]{ KOH(alc.) }  (A) \xrightarrow [ 770K ]{ { Cl }_{ 2 }(g) }  (X). (X) can be:
  • vinyl chloirde
  • allyl chloride
  • ethyl chloride
  • ethyl iodide
Ethanol \xrightarrow [  ]{ { P }_{ 4 }/{ I }_{ 2 } }  (X) \xrightarrow [ (ii)HBr ]{ (i)KOH(alc.) }  (Y)
In this sequence of reaction , (Y) is:
  • ethene
  • bromoethane
  • ethanol
  • none of these
{C}_{6}{H}_{5}Cl \xrightarrow [ 625K, \ 300atm ]{ NaOH(aq.) }  
The product can be:
  • benzal
  • sodium benzoate
  • benzol
  • sodium phenate
Which of the following is called Westron?
  • {CH}_{3}Cl
  • CH{Cl}_{3}
  • CH{Cl}_{2}.CH{Cl}_{2}
  • C{Cl}_{2}=CHCl
(X) on treatment with sodium hydroxide followed by the addition of silver nitrate gives white precipitate at room temperature which is soluble in {NH}_{4}OH. (X) can be:
  • chlorobenzene
  • ethyl bromide
  • benzyl chloride
  • vinyl chloride
Which of the following halides can yield ethane and also methane in a single step?
  • {C}_{2}{H}_{5}Br
  • {CH}_{3}I
  • { \left( { CH }_{ 3 } \right) }_{ 2 }CHBr
  • None
{CH}_{3}-CH(Cl)-{C}_{2}{H}_{5} \xrightarrow [  ]{ Alc.\quad KOH }  {CH}_{3}-CH=CH-{CH}_{3}
The above reaction proceeds via E_1cb mechanism?
  • It is second order and bumolecular
  • It is first order and unimolecular
  • It is first order an bimolecular
  • It is second order and unimolecular
The reaction of toluene with chlorine in the presence of ferric chloride gives predominantly:
  • Benzoyl chloride
  • m-chlorotoluene
  • Benzyl chloride
  • o- and p-chlorotoluene
For the reaction, C_2H_5OH+HX\overset{ZnX_2}{\longrightarrow} C_2H_5X, the order of reactivity is:
  • \;HI>HCl>HBr
  • \;HI>HBr>HCl
  • HCl>HBr>HI
  • \;HBr>HI>HCl
Tertiary butyl chloride undergoes S_{N}1 reactions immediately .
  • True
  • False
Allyl chloride is a .............. compound while vinyl chloride is inert towards nucleophilic substitution.
  • reactive
  • mildly reactive
  • not reactive
  • netural
Aryl halides are less reactive towards nucleophilic substitution reaction as compared to alkyl halides due to:
  • the formation of less stable carbonium ion
  • resonance stabilisation
  • longer carbon-halogen bond
  • the inductive effect
  • {sp}^{2}-hybridised carbon attached to the halogen
1,\:3- Dibromopropane reacts with metallic zinc to form:
  • propene
  • cyclopropane
  • propane
  • hexane
Vinyl chloride reacts with dilute NaOH to form vinyl alcohol.
  • True
  • False
Secondary butyl chloride undergo alkaline hydrolysis in the polar solvent by ___________ mechanism.
  • \:S_{N}2
  • \;S_{N}1
  • \;S_{N}1 and S_{N}2
  • \;E\ 2
1-phenyl-2-chloropropane on treating with alc. KOH gives mainly:
  • 1-phenylpropene
  • 2-phenylpropene
  • 1-phenylpropane-2-ol
  • 1-phenylpropan-1-ol
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