What is ${{C}_{2}}{{H}_{2}}$ hybridization?

Hint:When different atoms combine to form molecules the energy of their atomic orbitals is not the same, so they combine there is the formation of molecular orbitals having the same energy which is known as hybridization. We can calculate the hybridization by the number of different atoms with which it is joined.

Complete step-by-step answer:When different atoms combine to form molecules the energy of their atomic orbitals is not the same, so they combine there is a formation of molecular orbitals having the same energy which is known as hybridization.
${{C}_{2}}{{H}_{2}}$ is a compound of the homologous series alkyne and it is the first element of the alkyne group. The name of ${{C}_{2}}{{H}_{2}}$ is ethyne or acetylene. In ${{C}_{2}}{{H}_{2}}$, each carbon atom is joined with one hydrogen atom and the carbon atom is joined with itself. But the bond between the carbon and carbon atom is a triple bond.
By counting the number of bonds we can predict the hybridization, i.e., if all the bonds of the carbon atom is a single bond then the hybridization is $s{{p}^{3}}$, if one bond of the carbon atom is a double bond then the hybridization is $s{{p}^{2}}$, and if the carbon atom has a triple bond then the hybridization will be sp.
The structure of ethyne or acetylene is given below:
$H-C\equiv C-H$
There is a triple bond in the compound, then the hybridization is sp.

Note:All the elements of the period will have mostly hybridization in s and p orbitals, but higher elements of d-block, p-block, etc will involve the d-orbital also along with s and p-orbital.