Which of the following is aromatic? from Chemistry Hydrocarbons

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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.


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337.

Which of the following is aromatic?


B.

Aromaticity can be predicted by the use of Huckle's rule which says that (4n + 2) π- electrons  are required in delocalisation system to give it aromaticity. (4n+2) πelectrons mean 2,6,10....π electrons. Here total number of electron aviable for delocalisation = 6.

Therefore it is expected to be aromatic.


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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.


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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