The coordination number and the oxidation state of the element ‘E’ in the complex [E(en)2(C2O4)]NO2  (where)  (en) is ethylene diamane are, respectively,

In the given complex we have two bidentate ligands (i.e en and C2O4 ), so coordination number of E is 6 (2×2+1×2=6) Let the oxidation state of E in complex be x, then [x+(−2)=1] or                                  x−2=1 or x=+3,  so its oxidation state is + 3 Thus option (a) is correct.