Question

According to valence bond theory, the triple bond in ethyne (acetylene, C₂H₂) consists of

A) three s bonds and no p bonds.
B) two s bonds and one p bond.
C) one s bond and two p bonds.
D) no s bonds and three p bonds.
E) none of the above.

Answer 1

The triple bond in ethyne consists of one sigma bond and two pi bonds, according to valence bond theory. So the correct answer is option C.

Step-by-step explanation:

According to valence bond theory, the triple bond in ethyne (acetylene, C₂H₂) consists of one sigma ( σ ) bond and two pi ( π ) bonds.

This is because one sp-hybridized carbon atom overlaps with the sp-hybridized orbital of the other carbon atom to form a sigma bond along the axis of the orbital. The remaining unhybridized p orbitals on each carbon atom are parallel and overlap sideways to form two pi bonds.

Therefore, the correct answer to the student's question is C) one s bond and two p bonds, as shown in the structural formula of ethyne, where the triple bond comprises one sigma bond and two pi bonds between the carbon atoms.