Which of the following complexes is homoleptic?

The neutral ligand is

According to the Lewis theory,a ligand is .......

Three moles of $AgCl$ get precipitated when one mole of an octahedral coordination compound with empirical formula $CrCl_{3} \cdot 3NH_{3} \cdot 3H_{2}O$ reacts with excess of silver nitrate. The number of chloride ions satisfying the secondary valency of the metal ion is $......$

Define the following terms:
$1$. Coordination entity
$2$. Central metal ion

The sum of the oxidation state (magnitude) and the coordination number of cobalt in $Na[Co(bpy)Cl_4]$ is $.......$ (Given $bpy = 2,2'-bipyridine$)