Which of the following is not a chelating ligand?

What is the number of $N$ atoms present in $EDTA$?

The correct formula of potassium ferricyanide is:

The number of chloride ions produced in an aqueous solution of tetraamminedichloroplatinum $(IV)$ chloride is ...........

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 number of $Fe$ in the complexes $[Fe(CN)_6]^{4-}$,$[Fe(CN)_6]^{3-}$ and $[FeCl_4]^-$ would be respectively: