What is the number of moles of donor atoms in $n$ mole of $NO_2^{-}$?

What is the coordination number of $Co$ in $[CoCl_2(NH_3)_4]^+$?

Metals have the tendency to lose electrons to form cations. When $Zn$ is added to $NaOH$,a complex is formed. In this complex,$Zn$ is present in:

$A$ coordination complex compound of cobalt has a molecular formula containing five ammonia molecules,one nitro group,and two chlorine atoms for one cobalt atom. One mole of this compound produces three moles of ions in an aqueous solution,and upon reacting with an excess of $AgNO_3$,it forms $AgCl$ precipitate. The ionic formula for this complex would be:

The ligand $N(CH_2-CH_2-NH_2)_3$ is : $-$

Which of the following is not a chelating ligand?