Indicate which orbitals overlap to form the σ bond between the carbon atoms in HCCH

a. between an unhybridized s orbital on C and an unhybridized s orbital on the other C

b. between a hybrid sp orbital on C and a hybrid sp orbital on the other C

c. between a hybrid sp2 orbital on C and a hybrid sp2 orbital on the other C

The correct option is: b. between a hybrid sp orbital on C and a hybrid sp orbital on the other C

Explanation:

Acetylene is an unsaturated hydrocarbon molecule consisting of two carbon atoms bonded by a triple bond. It has a linear molecular structure.

H-C≡C-H

In this molecule, each carbon atom is sp hybridized and the sp hybridized orbital of one carbon atom overlaps with the sp hybridized orbital of the second carbon atom to form a sigma (σ) bond between the carbon atoms of a acetylene molecule.

Therefore, the sp hybridized orbitals of the two carbon atoms overlap to form a σ bond in an acetylene molecule.