Assertion : Alkyl benzene is not prepared by Friedel-Crafts alkyl

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 Multiple Choice QuestionsMultiple Choice Questions

331.

The length of C - C bond in benzene is :

  • 1.22 Ao

  • 1.54 Ao

  • 1.39 Ao

  • 1.56 Ao


332.

Which of the following is most stable ?

  • 1-butene

  • 1-pentene

  • 2-butene

  • 2-pentene


333.

The compound having only primary hydrogen atoms is

  • isobutene

  • 2,3-dimethylbutene

  • cyclohexane

  • propyne


334.

Among the following the aromatic compound is


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335.

Assertion : Styrene on reaction with HBr gives 2-bromo-2-phenyl ethane.

Reason: Benzyl radical is more stable than alkyl radical.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If resason is true but assertion is false

  • If both assertion and reason are false.


336.

Assertion : The pKa of acetic acid is lower than that of phenol.

Reason : Phenoxide ion is more resonance stabilised

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


337.

Which of the following is aromatic?


338.

Which ofthe following is most stable carbocation?

  • CH3+

  • CH3CH2C+H2

  • CH3C+HCH3

  • CH3-(CH3)C+-CH3


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339.

Assertion : Alkyl benzene is not prepared by Friedel-Crafts alkylation of benzene.

Reason : Alkyl halides are less reactive than acyl halides.

  • If both assertion and reason are true and the reason is the correct explanation of the assertion.

  • If both assertion and reason are true and the reason is not the correct explanation of the assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


B.

If both assertion and reason are true and the reason is not the correct explanation of the assertion.

The monoalkyl derivative first formed readily undergoes further alkylation at a still greater speed to produce polysubstituted products, and alkyl halide employed may also undergo an isomeric change. Due to these difficulties alkyl benzene is not generally prepared by Friedel-Craft's alkylation of benzene.


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340.

Rate determining step in nitration of benzene is

  • formation of NO2+

  • formation of carbocation

  • replacement of H atom

  • none of these.


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