Question

Explain whether chloroethene should be more or less reactive than chloroethane towards nucleophiles.

Answer 1

1. Chloroethene (vinyl chloride) has a chlorine atom attached to a carbon–carbon double bond (C=C), while chloroethane has chlorine attached to a saturated carbon (C–C single bond).
2. In chloroethene, the lone pair on chlorine overlaps with the adjacent π-electrons of the double bond, creating partial double bond character in the C–Cl bond.
3. This partial double bond makes the C–Cl bond in chloroethene stronger and less polar, so it is harder to break than the C–Cl bond in chloroethane.
4. The carbon bonded to Cl in chloroethene is sp² hybridized, which holds the electrons closer to the nucleus, making it less electron-deficient and less attractive to nucleophiles.
5. In contrast, chloroethane has an sp³ hybridized carbon, which is more electron-deficient and more easily attacked by nucleophiles.
6. The π-electrons in the double bond of chloroethene also tend to repel nucleophiles, further reducing the chances of substitution.

Therefore, chloroethene is less reactive than chloroethane towards nucleophilic substitution reactions.