Which among the following is a cationic complex?

$A$ coordination compound of cobalt contains five ammonia molecules,one nitro group,and two chlorine atoms per cobalt atom. One mole of this compound produces three moles of ions in an aqueous solution. Reaction of this solution with excess $AgNO_3$ yields two moles of $AgCl$ precipitate. What is the ionic structure of this complex?

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

Explain the concept of Primary Valency and Secondary Valency as proposed by Alfred Werner.

Identify the total number of complexes having bidentate ligands in them from the following list of complexes:
$a$) Tetracyanonickelate$(II)$ ion
$b$) Trioxalatocobaltate$(III)$ ion
$c$) Sodium hexafluoroaluminate$(III)$
$d$) bis(ethylenediamine)dithiocyanatoplatinum$(IV)$

Consider the complex $[Co(NH_3)_4 CO_3]ClO_4$. The coordination number,oxidation number,and number of $d$-electrons on the metal are respectively: