Question

Aluminum chloride in acidified aqueous solution forms a complex ‘A’, in which the hybridization state of aluminum is ‘B’. What are A and B, respectively?
A.\[{\left[ {Al{{\left( {{H_2}O} \right)}_6}} \right]^{3 + }},s{p^3}{d^2}\]
B.\[{\left[ {Al{{\left( {{H_2}O} \right)}_4}} \right]^{3 + }},s{p^3}\]
C.\[{\left[ {Al{{\left( {{H_2}O} \right)}_4}} \right]^{3 + }},ds{p^2}\]
D.\[{\left[ {Al{{\left( {{H_2}O} \right)}_6}} \right]^{3 + }},{d^2}s{p^3}\]

Answer 1

Hint: Aluminum chloride in aqueous solution forms a complex containing aluminum as a metal atom and water as ligands. The number of ligands is six. Thus, it is an octahedral complex and the hybridization involved is \[s{p^3}{d^2}\] , which means it is an outer orbital complex.

Complete answer:
Complex compounds are also known as coordination compounds. These are special type of compounds that can retain or do not lose their identity even dissolved in water or any other organic solvents. These compounds contain a metal atom as a central metal atom and ligands which are negatively or neutrally charged atoms or groups.
Aluminium is an element and undergoes oxidation to form an ion which can be called as a metal atom. Aluminium chloride is a salt and when treated with water forms a complex. The complex formed will be \[{\left[ {Al{{\left( {{H_2}O} \right)}_6}} \right]^{3 + }}\] , which has an aluminium as a central metal atom and water molecules as ligands. The aluminium is in \[ + 3\] oxidation state and forms \[6s{p^3}{d^2}\] hybrid orbitals. Thus, the hybridisation is \[s{p^3}{d^2}\] and the complex is \[{\left[ {Al{{\left( {{H_2}O} \right)}_6}} \right]^{3 + }}\].
A and B are \[{\left[ {Al{{\left( {{H_2}O} \right)}_6}} \right]^{3 + }}\] and \[s{p^3}{d^2}\].
Hence, option (A) is the correct answer.

Note:
Aluminium is a metal and can undergo oxidation easily which means the loss of electrons takes place. As the aluminium has \[3\] valence electrons, these \[3\] electrons can be easily lost and forms the six hybrid orbitals as the d-orbital is already involved in the aluminium. Thys, the hybridisation is \[s{p^3}{d^2}\] .