Example of vinylic halide is

Step 1: Define vinylic halide

A vinylic halide is a compound where the halogen (X) is directly attached to an $sp^2$ hybridized carbon atom of a carbon-carbon double bond ($\ce{C=C}$).

Step 2: Analyze each option

• Option (a): Shows a cyclohexene ring with X attached to one of the $sp^2$ carbons of the double bond. This is a vinylic halide.
• Option (b): Shows benzene with a $\ce{-CH2X}$ side chain. The halogen is on an $sp^3$ carbon (benzylic position), not vinylic.
• Option (c): Shows benzene with X directly attached to the aromatic ring. This is an aryl halide, not vinylic.
• Option (d): Shows cyclohexane (no double bond) with X attached. This is an alkyl halide, not vinylic.

Step 3: Conclusion

Only option (a) has the halogen attached to an $sp^2$ carbon of a $\ce{C=C}$ double bond.

Answer: (a)

Key Points:

• Vinylic halide: X on $sp^2$ carbon of $\ce{C=C}$
• Aryl halide: X on aromatic ring
• Benzylic halide: X on carbon adjacent to aromatic ring
• Alkyl halide: X on $sp^3$ carbon