Question

Calculate the oxidation state of a metal in the following complexes :

(a) [Fe(NH₃)₆](NO₃)₃

(b) Ni(CO)₅.

Answer 1

(a) [Fe(NH₃)₆](NO₃)₃ ⇌ [Fe(NH₃)₆]³⁺ + 3NO₃^-

NH₃ is a neutral ligand, and the charge number of complex ion is + 3. 

If the oxidation state of Fe is x then,

+ 3 = x + 6(0) 

∴ x = + 3 

∴ The oxidation state of Fe is +3.

(b) Ni(CO)₅ is a neutral complex and CO is a neutral ligand. 

If the oxidation state of Ni is x, then 

zero = x + 5 x (zero) 

∴ x = zero. 

The oxidation state of Ni is zero.