Question

Which among the following is benzylic halide?

• A. 4-Iodotoluene
• B. 1-Iodo-2-phenylethane
• C. Iodobenzene
• D. Iodophenylmethane

Hint:

Always distinguish between an aryl halide and a benzylic halide: In aryl halides ($\mathrm{Ar-X}$), the halogen is bound to an $\mathrm{sp^2}$ ring carbon. In benzylic halides ($\mathrm{Ar-C-X}$), the halogen is on a side-chain carbon immediately adjacent to the ring.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
We need to identify the chemical compound from the list that represents a benzylic halide structural configuration.

Step 2: Key Formula or Approach:
A

benzylic halide is a compound where a halogen atom is bonded directly to an $\mathrm{sp^3}$ hybridized carbon atom that is itself attached directly to an aromatic benzene ring ($\mathrm{Ar-CH_2-X}$).

Step 3: Detailed Explanation:
Let's structurally break down the structural connectivity of each option:

• 4-Iodotoluene: The iodine atom is bound directly to the $\mathrm{sp^2}$ aromatic carbon of the toluene ring opposite to the methyl group. This is an aryl halide.

• 1-Iodo-2-phenylethane: The structure is $\mathrm{C_6H_5-CH_2-CH_2-I}$. The iodine is on an $\mathrm{sp^3}$ carbon, but that carbon is separated from the aromatic ring by an intervening $\mathrm{-CH_2-}$ group. This is a regular aliphatic halide.

• Iodobenzene: The iodine is bonded directly to the aromatic carbon ring ($\mathrm{C_6H_5I}$). This is a simple aryl halide.

• Iodophenylmethane: Also known commonly as benzyl iodide, its structure is $\mathrm{C_6H_5-CH_2-I}$. Here, the iodine atom is directly connected to the methyl carbon ($\mathrm{sp^3}$ hybridized), which is directly linked to the phenyl ring. This perfectly matches the criteria for a benzylic halide.

Step 4: Final Answer:
The compound that is a benzylic halide is Iodophenylmethane, which corresponds to option (D).