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: Recall the benzylic rule.
A halide is benzylic only when the halogen sits on an $sp^3$ carbon bonded straight to the benzene ring. If a spacer carbon comes between, it is plain aliphatic.
Step 2: We are hunting the exception.
The question asks which one is NOT benzylic, so we keep the three that fit and flag the odd one.
Step 3: Check 2-chloro-2-phenylpropane.
$C_6H_5-C(Cl)(CH_3)_2$, the chlorine carbon touches the ring directly, so this is benzylic, keep.
Step 4: Check chlorophenyl methane and 1-chloro-1-phenylethane.
Benzyl chloride $C_6H_5-CH_2-Cl$ and $C_6H_5-CH(Cl)-CH_3$ both have the chlorine carbon joined straight to the ring, both benzylic, keep.
Step 5: Check 1-chloro-2-phenylbutane.
$Cl-CH_2-CH(C_6H_5)-CH_2-CH_3$. The chlorine is on carbon $1$, but the phenyl is on carbon $2$. A carbon separates the halogen from the ring, so it is aliphatic, not benzylic.
Step 6: Name the odd one out.
The compound that fails the benzylic test is $1$-chloro-2-phenylbutane.
\[ \boxed{1\text{-Chloro-2-phenylbutane (option B)}} \]