Which one will give $Fe^{3+}$ ions in solution?

The stabilization of coordination compounds due to chelation is called the chelate effect. Which of the following is the most stable complex species?

$A$ solution containing $2.675 \ g$ of $CoCl_3 \cdot 6 NH_3$ (molar mass $= 267.5 \ g \ mol^{-1}$) is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of $AgNO_3$ to give $4.78 \ g$ of $AgCl$ (molar mass $= 143.5 \ g \ mol^{-1}$). The formula of the complex is
(At. mass of $Ag = 108 \ u$)

The solubility of $AgCl$ in $NH_4OH$ is due to the formation of:

Which of the following ions is the most stable?

Select the correct statement regarding the $[Ni(DMG)_2]$ complex compound.