Question

question #5
use valence bond theory to explain the bonding in h₂cch₂.
the σ bond between the carbon atoms is due to overlap of orbitals.
the π bonds between the carbon atoms are due to overlap of orbitals.

Explanation:

• For the $\sigma$ bond: In $H_2CCH_2$ (ethyne), each carbon atom is $sp$ hybridized. The $sp$ hybrid orbitals are involved in the formation of $\sigma$ bonds. One $sp$ hybrid orbital of each carbon atom overlaps head - on to form the $C - C$ $\sigma$ bond.
• For the $\pi$ bonds: The un - hybridized $p$ orbitals (two $p$ orbitals on each carbon atom) are perpendicular to the axis of the $sp$ hybrid orbitals. These $p$ orbitals overlap sideways (lateral overlap) to form $\pi$ bonds.

Answer:

• The $\sigma$ bond between the carbon atoms is due to overlap of $sp$ orbitals.
• The $\pi$ bonds between the carbon atoms are due to overlap of $p$ orbitals.