How many $EDTA$ molecules are required to form an octahedral complex with a $Ca^{2+}$ ion?

Write a note on chelating ligands.

The number of ions formed when cuprammonium sulphate is dissolved in water is

$A$ complex compound of $Co^{3+}$ with molecular formula $CoCl_{x} \cdot yNH_3$ gives a total of $3$ ions when dissolved in water. How many $Cl^{-}$ ions satisfy both primary and secondary valencies in this complex?

Explain the concept of Primary Valency and Secondary Valency as proposed by Alfred Werner.

The charge on the $[Ag(CN)_2]^-$ complex is: