The coordination number and the oxidation state of the element E in the complex [E(en)_{2}(C_{2}O_{4})]NO_{2} (where (en) is ethylene diamine) are, respectively

- 6 and 3
- 4 and 2
- 4 and 3
- 6 and 2

**Answer**

In the given complex [E(en)_{2}(C_{2}O_{4})]^{+}NO_{2}^{-} ethylene diamine is a bidentate ligand and (C_{2}O_{4}^{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

x = 3

**The correct option is A.**