Which one of the following is not a consequence of hybridization?

enhanced reactivity of the molecule

The correct answer is option 4. enhanced reactivity of the molecule.

Hybridization affects various properties of molecules, but not all properties listed are direct consequences of hybridization. Let us analyze each option to identify the one that is not a direct consequence of hybridization:

1. Effective Overlapping of Orbitals

Hybridization involves the mixing of atomic orbitals to form new hybrid orbitals that are oriented in specific geometries. This reorientation facilitates more effective overlapping when these hybrid orbitals bond with orbitals from other atoms. For example, in a molecule of methane (\(CH_4\)), carbon undergoes \(sp^3\) hybridization, forming four \(sp^3\) hybrid orbitals that overlap effectively with the 1s orbitals of hydrogen atoms, resulting in strong sigma (\(\sigma\)) bonds.

Consequence of Hybridization: Yes, effective overlapping of orbitals is a direct consequence of hybridization. The formation of hybrid orbitals with specific orientations increases the overlap integral, thereby strengthening the bonds.

2. Minimized Repulsion Between Orbital Electrons

Hybridization allows for the spatial arrangement of orbitals such that electron pairs (both bonding and lone pairs) are as far apart as possible, minimizing electron-electron repulsion according to the VSEPR (Valence Shell Electron Pair Repulsion) theory. For instance, in a tetrahedral geometry (\(sp^3\) hybridization), the bond angles are approximately 109.5°, which maximizes the separation between electron pairs and minimizes repulsion.

Consequence of Hybridization: Yes, minimizing repulsion between orbital electrons is a consequence of hybridization. By adopting hybrid orbitals that lead to specific geometric arrangements, hybridization helps reduce electron pair repulsion.

3. Stronger Bonds

The hybridization process creates orbitals that have better directional properties, allowing for stronger and more stable bonds through greater overlap. For example, in ethene (\(C_2H_4\)), carbon atoms use \(sp^2\) hybrid orbitals to form sigma bonds with hydrogen and each other. The unhybridized p orbitals on each carbon overlap side-to-side to form a pi (\(\pi\)) bond, further stabilizing the molecule.

Consequence of Hybridization: Yes, stronger bonds are a consequence of hybridization. The formation of hybrid orbitals with appropriate geometries and orientations leads to stronger covalent bonds due to more effective orbital overlap.

4. Enhanced Reactivity of the Molecule

The reactivity of a molecule depends on multiple factors including the nature of the bonds, the presence of functional groups, electronic distribution, and steric factors. While hybridization can influence the geometry and bond angles in a molecule, it does not directly dictate the reactivity. For instance, \(sp^3\)-hybridized carbon in methane is relatively non-reactive, while \(sp^2\)-hybridized carbon in ethene is more reactive due to the presence of a double bond.

Consequence of Hybridization: No, enhanced reactivity of the molecule is not a direct consequence of hybridization. Reactivity is influenced by various chemical and physical properties of the molecule, and while hybridization affects bond strength and geometry, it does not directly enhance reactivity.

Hybridization directly leads to:

1. Effective overlapping of orbitals.

2. Minimized repulsion between orbital electrons.

3. Stronger bonds.

However, hybridization does not directly cause enhanced reactivity of a molecule. Therefore, the correct answer is 4. Enhanced reactivity of the molecule.