Hemoglobin is a complex of

Which ligand is used in the estimation of the hardness of water?

Write the application of coordination compounds in black and white photography.

The reagent used for the detection of $Ni^{2+}$ is $A$. $x$ moles of $A$ react with $Ni^{2+}$ to form a complex of $C$ color. $A$,$x$,and $C$ are respectively:

Identify the use of $EDTA$ from the following.

Match the metal in column $I$ with the coordination compounds/enzymes in column $II$.

Column $I$ (Metals)	Column $II$ (Coordination compounds)
$a. Co$	$i. \text{Wilkinson catalyst}$
$b. Zn$	$ii. \text{Chlorophyll}$
$c. Rh$	$iii. \text{Vitamin } B_{12}$
$d. Mg$	$iv. \text{Carbonic anhydrase}$