Question

Which of the following statements is not correct about $AlC{l}_3$?

• A. It exists as a dimer
• B. It is a covalent compound
• C. It involves back bonding between $Cl$ and $Al$
• D. Its aqueous solution conducts electricity

Answer 1

The correct option is C It involves back bonding between $Cl$ and $Al$

Back bonding occurs between the same size of orbitals of small atoms. 3p orbitals of $Al$ and $Cl$ are comparatively larger. In case of $AlC{l}_3$, the octet of $Al$ is completed by dimerisation. Here, one of the lone pairs of $Cl$ atom is donated to the vacant 3p orbital of $Al$ atom of other $AlC{l}_3$ molecule. So, back bonding doesn't occur in $AlC{l}_3$.

Hence, option $C$ is correct.