The oxidation state and covalency of Al in [AlCl (H₂O)₅]²⁺ are
+ 3 and 3
+ 3 and 6
+ 2 and 6
+ 2 and 1
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Answer is Wrong!
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UPSC Geoscientist – 2023
Let the oxidation state of Aluminum (Al) be x.
The charge of the chloride ligand (Cl⁻) is -1.
The charge of the water ligand (H₂O) is 0 (neutral molecule).
The overall charge of the complex ion is +2.
The sum of the oxidation states of the central metal ion and the charges of the ligands equals the overall charge of the complex:
x + (charge of Cl) + 5 * (charge of H₂O) = +2
x + (-1) + 5 * (0) = +2
x – 1 = +2
x = +3
So, the oxidation state of Al in [AlCl (H₂O)₅]²⁺ is +3.
The covalency of the central metal atom/ion in a coordination complex is equal to its coordination number, which is the total number of sigma bonds formed between the metal and the ligands. This is typically the number of ligands directly attached to the central metal.
In [AlCl (H₂O)₅]²⁺, the Al³⁺ ion is bonded to one Cl⁻ ligand and five H₂O ligands.
Total number of ligands attached = 1 + 5 = 6.
The coordination number of Al is 6.
Therefore, the covalency of Al in this complex is 6.
The oxidation state is +3 and the covalency is 6.