Describe the change in hybridization (if any) of the $Al$ atom in the following reaction:
$AlCl_3 + Cl^{-} \to AlCl_4^-$

(N/A) In the gaseous state,$AlCl_3$ exists as a dimer $Al_2Cl_6$,where each $Al$ atom is $sp^3$ hybridized.
In the reaction $AlCl_3 + Cl^{-} \to AlCl_4^-$,the $Al$ atom in the product $AlCl_4^-$ also exhibits $sp^3$ hybridization.
Therefore,there is no change in the hybridization of the $Al$ atom during this reaction.