Question

In which of the following dimer empty atomic orbital of the central atom of monomer does not involve hybridization?
A) $\text{G}{{\text{a}}_{2}}{{\text{H}}_{6}}$
B) $\text{A}{{\text{l}}_{2}}\text{B}{{\text{r}}_{6}}$
C) $\text{B}{{\text{e}}_{2}}{{\text{H}}_{6}}$
D) $\text{C}{{\text{l}}_{2}}{{\text{O}}_{6}}$

Answer 1

Hint : In $\text{G}{{\text{a}}_{2}}{{\text{H}}_{6}}$ , $\text{A}{{\text{l}}_{2}}\text{B}{{\text{r}}_{6}}$ , $\text{B}{{\text{e}}_{2}}{{\text{H}}_{6}}$ and $\text{C}{{\text{l}}_{2}}{{\text{O}}_{6}}$ the central atoms are gallium(atomic number-31), aluminum (atomic number-13), beryllium ( atomic number-4) and chlorine ( atomic number-17) respectively. When the central atom is in an excited state, one electron of filled orbitals jumps to an empty orbital to form hybrid orbitals.

Complete Step By Step Answer:
We are given $\text{G}{{\text{a}}_{2}}{{\text{H}}_{6}}$ , $\text{A}{{\text{l}}_{2}}\text{B}{{\text{r}}_{6}}$ , $\text{B}{{\text{e}}_{2}}{{\text{H}}_{6}}$ and $\text{C}{{\text{l}}_{2}}{{\text{O}}_{6}}$ .
In $\text{G}{{\text{a}}_{2}}{{\text{H}}_{6}}$ , $\text{Ga}$ is the central atom whose electron configuration $\left( \text{Ar} \right)\text{3}{{\text{d}}^{10}}\text{4}{{\text{s}}^{2}}\text{4}{{\text{p}}^{1}}$ when the atom reaches excited state the electron in s-orbital jumps to the p-orbital and forms $\text{s}{{\text{p}}^{3}}$ hybridization so the empty orbital participates in hybridization. In $\text{A}{{\text{l}}_{2}}\text{B}{{\text{r}}_{6}}$ . The electronic configuration of $\text{Al}$ is $\left( \text{Ne} \right)3{{\text{s}}^{2}}\text{3}{{\text{p}}^{1}}$ which is the central atom. Its electron also jumps from s to p orbital to form $\text{s}{{\text{p}}^{3}}$ hybridization.
The same happens with $\text{B}{{\text{e}}_{2}}{{\text{H}}_{6}}$ whose empty orbital participates in hybridization. It also has $\text{s}{{\text{p}}^{3}}$ hybridization. $\text{C}{{\text{l}}_{2}}{{\text{O}}_{6}}$ is known as dichlorine hexoxide. It is found in the form of dimer in its gaseous state. In liquid or solid form, it oxidizes into a dark red ionic compound which is red due to presence of chloride ions. In this chlorine is the central atom whose electrons do not jump even in an excited state to form $\text{s}{{\text{p}}^{3}}$ hybridization and remain empty..
Hence the correct answer is “D”.

Additional Information:
Dimers are the compounds with two similar or identical monomer units joined by a covalent bond. Dimer $\text{C}{{\text{l}}_{2}}{{\text{O}}_{6}}$ is the correct formula for its gaseous state. It is diamagnetic in nature and is a very strong oxidizing agent. It is stable at room temperature. But it explodes when it comes in contact with organic compounds. It also acts as a source of $\text{Cl}{{\text{O}}_{3}}$ radical.

Note :
The student may get confused due to the same hybridization in all the compounds but there is a difference. The empty orbitals of the first three compounds participate in hybridization but the empty orbital of chlorine does not participate in the hybridization.