What is the formula of sodium nitroprusside?

The number of donor sites in dimethyl glyoxime,glycinato,diethylene triamine and $EDTA$ are respectively:

According to the Lewis theory,a ligand is .......

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

Number of water molecules in Mohr's salt is

Enlist the main postulates of Werner's theory.