Identify a ligand having two donor atoms but uses a pair of electrons of either donor atom to form a coordinate bond.

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

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

When $AgNO_3$ is added to an aqueous solution of a platinum complex,$1/4$ of the total chlorine content is precipitated. Determine the formula of the platinum complex from the given options.

Explain the terms 'Coordination Entity' and 'Central Atom/Ion' in the context of coordination compounds.

The conductivity of a solution of a complex with the formula $CoCl_3(NH_3)_4$ corresponds to a $1:1$ electrolyte. What is the primary valency of the central metal ion?