Which among the following is the strongest ligand?

Which of the following ions forms the most stable complex compound?

$A$ complex containing $K^{+}$,$Pt(IV)$ and $Cl^{-}$ is $100\%$ ionised giving $i = 3$. Thus,the possible complex is

If $1/3$ of the total chlorine in the compound is precipitated on adding $AgNO_3$ to its aqueous solution,which of the following is the correct structure of $CrCl_3 \cdot 6H_2O$?

During the estimation of nickel,we prepare nickel dimethylglyoxime,a scarlet red solid. This compound is . . . . . . .

$PbCl_{2}$ is insoluble in cold water. Addition of $HCl$ increases its solubility due to