Chemistry - CHEMICAL BONDING Question with Solution | TestHub

The question asks to identify the incorrect statement regarding the structure of $A{l}_{2}C{l}_6$.

The structure of $A{l}_{2}C{l}_6$ is a dimer where two $AlC{l}_3$ units are linked by two chlorine bridges. Each aluminum atom is $s{p}^3$ hybridized and surrounded by four chlorine atoms in a tetrahedral geometry.

Let's analyze each option:

A. It is a non-planar molecule.

This statement is correct. Due to the tetrahedral geometry around each aluminum atom, the molecule as a whole is non-planar.

B. Vacant orbital of Al participates in hybridization.

This statement is correct. Aluminum in $AlC{l}_3$ has an incomplete octet. In $A{l}_{2}C{l}_6$, the aluminum atoms use their vacant 3p orbitals to accept lone pairs from the bridging chlorine atoms, forming coordinate covalent bonds. This involves $s{p}^3$ hybridization.

C. It has 3c-4e⁻ and 2c-2e⁻ bonds.

This statement is correct. The terminal Al-Cl bonds are 2-center, 2-electron (2c-2e⁻) bonds. The bridging Al-Cl-Al bonds are 3-center, 4-electron (3c-4e⁻) bonds, where two electrons from the bridging chlorine atom are shared with two aluminum atoms.

D. $A{l}_{2}C{l}_6$ is an electron deficient molecule.

This statement is incorrect. In $A{l}_{2}C{l}_6$, each aluminum atom achieves an octet by forming four bonds (two terminal and two bridging). Therefore, it is not electron deficient. The monomer $AlC{l}_3$ is electron deficient, but its dimer $A{l}_{2}C{l}_6$ is not.

The final answer is $\boxed{D}$