Which of the following ligands is not ambidentate?
$(P) = NO_3^-$,$(Q) = NO_2^-$,$(R) = CN^-$,$(S) = SCN^-$

Which of the following is a negative ligand?

$2.33 \ g$ of compound $X$ (empirical formula $= CoH_{12}N_{4}Cl_{3}$) upon treatment with excess $AgNO_{3}$ solution produces $1.435 \ g$ of a white precipitate. The primary and secondary valences of cobalt in compound $X$,respectively are.
[Given,atomic mass : $Co = 59, Cl = 35.5, Ag = 108$]

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 $......$

Assertion : $A$ chelating ligand must possess two or more lone pairs at such a distance that it may form suitable strain-free rings at the metal ion.
Reason : $H_2N-NH_2$ is a chelating ligand.

The neutral ligand is