Question

The coordination number and the oxidation state of the element E in the complex [E(en)₂(C₂O₄)]NO₂(where (en) is ethylene diamine) are, respectively
(a) 6 and 3 

(b) 6 and 2

(c) 4 and 2 

(d) 4 and 3

Answer 1

(a) : In the given complex [E(en)₂(C₂O₄)] +NO₂^- ethylene diamine is a bidentate ligand and (C₂O₄^2–) oxalate ion is also bidentate ligand. Therefore coordination number of the complex is 6 i.e., it is an octahedral complex.
Oxidation number of E in the given complex is
x + 2 × 0 + 1 × (–2) = +1
Therefore, x = 3