JEE Main · 2024 · 30 Jan 2024 · Shift 1 · Haloalkanes and Haloarenes

A vinylic halide is an organic halide in which the halogen atom is directly attached to an sp²-hybridized carbon atom of a C=C double bond (vinyl carbon).

General structure: $\mathrm{R}-\mathrm{CH}=\mathrm{CH}-\mathrm{X}$ where X is a halogen.

Analyzing the options:

Option (1): Shows a halogen (X) directly attached to a carbon that is part of a C=C double bond in an aliphatic system. This is a vinylic halide.

Option (2): Shows a halogen attached to an sp³ carbon adjacent to a double bond. This is an allylic halide ($\mathrm{R}-\mathrm{CH}=\mathrm{CH}-\mathrm{C}{\mathrm{H}}_2-\mathrm{X}$).

Option (3): Shows a halogen directly attached to a benzene ring. This is an aryl halide.

Option (4): Shows a halogen attached to an sp³ carbon in a cyclic system with a double bond elsewhere. This is also an allylic halide.

The key distinction:

• Vinylic: X on sp² carbon of C=C (option 1)
• Allylic: X on sp³ carbon adjacent to C=C (options 2, 4)
• Aryl: X on aromatic ring (option 3)

Therefore, the correct answer is (1).