The given ligand is:

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

Give the chemical formulas for the following:
$(i)$ Sodium nitroprusside
$(ii)$ The purple solution formed in the test for sulphur
$(iii)$ Sodium hexacyanoferrate $(II)$
$(iv)$ Iron $(III)$ hexacyanoferrate $(II)$
$(v)$ Ferri-ferrocyanide
$(vi)$ Sodium thiocyanate

Which of the following ligands are ambidentate?
$P: NO_3^-$,$Q: NO_2^-$,$R: CN^-$,$S: SCN^-$

The molecular formula of tris(ethylenediamine)cobalt$(III)$ sulfate is:

The primary and secondary valencies of cobalt respectively in $[Co(NH_3)_5Cl]Cl_2$ are :