Question

Which among the following is NOT benzylic halide?

• A. 2-Chloro-2-phenylpropane
• B. 1-Chloro-2-phenylbutane
• C. Chlorophenyl methane
• D. 1-Chloro-1-phenylethane

Hint:

To verify a benzylic halide from its IUPAC name, check the numbers assigned to the halide and the phenyl group. If both substituents are located on the exact same carbon position (such as 1-chloro-1-phenyl... or 2-chloro-2-phenyl...), it is a benzylic halide. If the numbers are different (like 1-chloro-2-phenyl...), the halogen is located further down the chain!

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify the single compound from the given choices that does

not meet the structural criteria required to be classified as a benzylic halide.

Step 2: Key Formula or Approach:
By structural definition, a compound is classified as a

benzylic halide if and only if the halogen atom ($\mathrm{-X}$) is directly bonded to an $\mathrm{sp^3}$ hybridized side-chain carbon atom that is itself linked directly to an aromatic benzene ring. If the halogen sits on a position further down the alkyl chain, it is classified as an ordinary aliphatic alkyl halide instead.

Step 3: Detailed Explanation:
Let's review the connectivity of each option:

• 2-Chloro-2-phenylpropane: The structure is $\mathrm{C_6H_5-C(Cl)(CH_3)_2}$. The chlorine atom is on a carbon directly bound to the phenyl ring. (Benzylic halide)

• 1-Chloro-2-phenylbutane: The structure is $\mathrm{Cl-CH_2-CH(C_6H_5)-CH_2-CH_3}$. Here, the chlorine atom is bonded to Carbon-1, whereas the phenyl ring is attached to Carbon-2. Because the carbon holding the halogen is separated from the aromatic ring by an intervening carbon atom, it is an aliphatic primary alkyl halide,

not a benzylic halide.

• Chlorophenyl methane: Commonly known as benzyl chloride ($\mathrm{C_6H_5-CH_2-Cl}$). The chlorine is attached to the carbon adjacent to the ring. (Benzylic halide)

• 1-Chloro-1-phenylethane: The structure is $\mathrm{C_6H_5-CH(Cl)-CH_3}$. The chlorine atom is located on the carbon directly connected to the phenyl ring. (Benzylic halide)
Therefore, 1-chloro-2-phenylbutane is the only compound that is not a benzylic halide.

Step 4: Final Answer:
The compound that is NOT a benzylic halide is 1-Chloro-2-phenylbutane, corresponding to option (B).