The length of C - C bond in benzene is :

• 1.22 A^o

• 1.54 A^o

• 1.39 A^o

• 1.56 A^o

Which of the following is most stable ?

• 1-butene

• 1-pentene

• 2-butene

• 2-pentene

The compound having only primary hydrogen atoms is

• isobutene

• 2,3-dimethylbutene

• cyclohexane

• propyne

Among the following the aromatic compound is

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.

Assertion : The pK_a 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?

• 

• 

• 

• 

Which ofthe following is most stable carbocation?

• CH₃⁺

• CH₃CH₂$\stackrel{+}{\mathrm{C}}$H₂

• CH₃$$\begin{gathered} \stackrel{ \\ +}{\mathrm{C}} \end{gathered}$$HCH₃

• CH₃-(CH₃)$\stackrel{+}{\mathrm{C}}$-CH₃

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.

Rate determining step in nitration of benzene is

• formation of NO₂⁺

• formation of carbocation

• replacement of H atom

• none of these.