Which of the following ligands is neutral?

What is the coordination number of cobalt in $[Co(en)_2Br_2]Cl_2$?

Select the correct statements about the $PtCl_4 \cdot 4NH_3$ complex salt:
$I.$ All the chlorides are bonded by primary valency.
$II.$ All the chlorides are bonded by secondary valency.
$III.$ All the $NH_3$ are bonded by secondary valency.
$IV.$ Half of the chlorides are bonded with secondary valency.

The coordination numbers of $Fe$ in the complexes $[Fe(CN)_6]^{4-}$,$[Fe(CN)_6]^{3-}$,and $[FeCl_4]^{-}$ are respectively:

Which among the following statements is wrong regarding Mohr's salt?

Identify the anionic ligand from the following.