Question

Consider the following Lewis acid-base reaction, \[AlC{l_3} + C{l^ - } \to AlCl_4^ - \]. Hybridization of \[Al\]in \[AlC{l_3}\]and \[AlCl_4^ - \]are respectively:
A. \[s{p^3},ds{p^2}\]
B. \[s{p^2},ds{p^2}\]
C. \[ds{p^2},s{p^3}d\]
D. \[s{p^2},s{p^3}\]

Answer 1

Hint: The Lewis acid reacts with the Lewis base and then forms an acid-base compound that changes the p-orbital from lower to higher degree.

Complete Step by Step Solution:
Lewis acid-base reaction:
1. In Lewis acid-base reactions, a base donates electrons to acid and forms Lewis acid-base adduct.
2. In a Lewis acid-base adduct, a coordinate covalent bond is formed between the Lewis base and acid.

Hybridization:
1. Intermixing of orbitals with slightly different energies, resulting in a new set of orbitals with equally strong energies and shapes created through redistribution of energies.
2. For example, if there are one 2s and three 2p-orbitals of the element hybridize then there is a formation of \[s{p^3}\]hybrid orbitals.

Hybridization of \[Al\]in \[AlC{l_3}\]and \[AlCl_4^ - \]:
1. In the given reaction, \[AlC{l_3}\]acts as a Lewis acid and \[Al\]acts as a Lewis base. There is a formation acid-base adduct (\[AlCl_4^ - \]).
2. The aluminium trichloride at the excited state has one 2s and two 2p-orbitals so it has \[s{p^2}\]hybrid orbitals.
3. There are one 2s and three 2p-orbitals of aluminium tetrachloride at the excited state that forms \[s{p^3}\]hybrid orbitals.
4. The shape of the \[AlC{l_3}\]and \[AlCl_4^ - \]is a trigonal planar and tetrahedral structure.
Thus, the option (D) is correct.

Additional information:
1. There are basically three types of hybridization which are \[sp,s{p^2},s{p^3}\].
2. The types of hybridization also indicate the geometry of the compounds.
3. There are basically three types of hybridization that involve d-orbital that are \[ds{p^2},s{p^3}d,s{p^3}{d^2}\] but the last one has two different structures.
4. The structure of \[sp,s{p^2},s{p^3}\]are linear, triangular, and tetrahedral.
5. The structures of d-orbital hybridization are square planar, trigonal bipyramidal, square pyramidal, and octahedral.

Note: The number of hybrid orbitals is equal to the number of atomic orbitals which are to be hybridised and also hybridization orbitals are equivalent in energy and shape.