Which of the following is an ambidentate ligand?

The complex $[Pt(NH_3)_6]Cl_4$ furnishes $.......$ ions.

Explain the following term with an example: Hexadentate ligands.

Which of the following is a negative ligand?

$A$ 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?

Which of the following coordination compounds will yield the maximum amount of $AgCl$ upon reaction with an excess of $AgNO_3$ for $1 \ mol$ of the compound?