In $K_4[Ni(C_2O_4)_3]$,what is the sum of the coordination number and the oxidation number of $Ni$?

The coordination number of copper in cuprammonium sulfate is.....

Which among the following complexes is heteroleptic and cationic in nature?

Total number of moles of $AgCl$ precipitated on addition of excess of $AgNO_3$ to one mole each of the following complexes $[Co(NH_3)_4Cl_2]Cl$,$[Ni(H_2O)_6]Cl_2$,$[Pt(NH_3)_2Cl_2]$ and $[Pd(NH_3)_4]Cl_2$ is $...............$ (in $.00$)

What are the coordination number and oxidation state of $E$ in the complex $[E(en)_2(C_2O_4)]NO_2$?

Identify the neutral complex from the following.