What is the percentage of 's' character in the carbon atom of acetylene?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 50%.
In acetylene (C₂H₂), each carbon atom forms two sigma bonds (one with hydrogen and one with another carbon) and two pi bonds (between the carbon atoms). The carbon atoms are sp-hybridized, meaning one s-orbital and one p-orbital combine to form two sp hybrid orbitals.
In sp hybridization, the contribution of the s-character is:
s-character = (1 s-orbital / total 2 orbitals) × 100 = 50%
So, each carbon atom in acetylene has 50% s-character in its hybrid orbitals, which makes the bonds shorter and stronger due to closer electron density to the nucleus.