In vinyl chloride, the carbon atom bonded to the chlorine atom (C1) is sp2 hybridized due to the presence of the double bond. sp2 hybridization involves the mixing of one s orbital and two p orbitals, resulting in three equivalent hybrid orbitals arranged in a trigonal planar geometry. These hybrid orbitals form strong sigma bonds with the adjacent atoms, including the chlorine atom.
On the other hand, in ethyl chloride, the carbon atom bonded to the chlorine atom (C1) is sp3 hybridized. sp3 hybridization involves the mixing of one s orbital and three p orbitals, resulting in four equivalent hybrid orbitals arranged in a tetrahedral geometry. These hybrid orbitals also form sigma bonds with the adjacent atoms, including the chlorine atom.
The difference in hybridization between the carbon atoms affects the C-Cl bond length. In vinyl chloride, the sp2 hybridized carbon atom has a more concentrated electron density in the region where the bond is formed compared to the sp3 hybridized carbon atom in ethyl chloride. This increased electron density leads to stronger electrostatic attraction between the carbon and chlorine atoms, resulting in a shorter C-Cl bond length in vinyl chloride.
Additionally, the presence of the double bond in vinyl chloride contributes to the shortening of the C-Cl bond. The double bond withdraws electron density from the C-Cl bond, making the chlorine atom more electronegative and enhancing its attraction towards the carbon atom. This further strengthens the C-Cl bond and contributes to its shorter length.
In summary, the shorter C-Cl bond length in vinyl chloride compared to ethyl chloride is a consequence of sp2 hybridization of the carbon atom, increased electron density, and the electron-withdrawing effect of the double bond.
