Haloalkanes and Haloarenes — Class 12 Chemistry PYQs

Which of the following is a benzylic halide ?
(A) [Phenethyl halide]
(B) [o-halotoluene]
(C) [m-halotoluene]
(D) [1-halo-1-phenylpropane]

Which of the following alkyl halides will undergo SN₁ reaction most readily ?
(A) (CH₃)₃ – I
(B) (CH₃)₃ – Cl
(C) (CH₃)₃ – Br
(D) (CH₃)₃ – F

Butanenitrile may be prepared by heating :
(A) propyl chloride with KCN
(B) butyl chloride with KCN
(C) propyl alcohol with KCN
(D) butyl alcohol with KCN

Which of the following contains sp² hybridised carbon bonded to X ?
(A) CH₂ = CH – CH₂ – X
(B) [Chlorobenzene]
(C) CH₂ = CH – X
(D) CH₃ – CH₂ – X

The compound which undergoes SN₁ reaction most rapidly is :
(A) [Cyclohexyl bromide]
(B) [Cyclohexyl methyl bromide]
(C) [Cyclohexyl bromide]
(D) [Cyclohexyl bromide]
(Note: Text descriptions used as images not provided. Options imply structures)

Which of the following is most reactive towards nucleophilic substitution reaction ?
(A) [Chlorobenzene]
(B) CH₃ – CH₂ – CH₂ – Cl
(C) CH₂ = CH – Cl
(D) CH₂ = CH – CH₂ – Cl

(a) Which one of the following pairs of substances undergoes SN₁ reaction faster and why ?
CH₃–CH₂–CH₂–Cl OR CH₂=CH–CH₂–Cl

(b) Write the major product in the following :
[p-chloronitrobenzene] $\underset{\text{(ii) H⁺}}{\overset{\text{(i) NaOH, 443 K}}{\to }}$ ?

(a) In the following pair of compounds, which compound undergoes SN₁ reaction faster and why ?
[Chlorobenzene]–CH₂Cl OR [Cyclohexyl]–CH₂Cl

(b) Write the major product in the following :
[Cyclohexene] $\stackrel{\text{Br₂, UV light}}{\to }$ ?

(a) Draw the structures of major monohalo products in each of the following reactions :

(i) [Benzene ring with vinyl group] + HBr →

(ii) [Cyclohexane ring with methyl group] + Br₂ $\stackrel{\text{UV light}}{\to }$ ?

OR

(b) Give reasons for the following :
(i) Grignard reagent should be prepared under anhydrous conditions.
(ii) Alkyl halides give alcohol with aqueous KOH whereas in the presence of alcoholic KOH, alkenes are formed.

Give reasons for the following :
(a) Chlorine is ortho/para directing in electrophilic aromatic substitution reactions, though chlorine is an electron withdrawing group.
(b) Racemic mixture is optically inactive.
(c) Allyl chloride is hydrolysed more readily than n-propyl chloride.